I had the same problem with my son (now 8).  I found the library to be the answer.  The books he first became interested in were written by Tedd Arnold, particularly "Even More Parts".  Silly, funny, not too many words on the page, good illustrations this book shows what would happen if commonly used expressions actually happened (i.e. "I've got a frog in my throat").  Once this sparked his interest, we moved onto beginning reader silly joke/riddle books.  "My Head is Red and Other Riddle Rhymes" was a favorite and got him reading and thinking.

google *dyslexia*, some of the things you describe is what was happening to my son.  I had him tested and he has dyslexia.  the Barton's reading system is made for a dyslexic child.  There are a lot of websites online.  Please research, and have your child tested.

Reading is a skill that needs to be practiced regularly. Without practice, young readers will not develop the vocabulary, the skills, and the fluency necessary to become strong readers.  But many children, even those with strong reading skills, do not get enough practice and as a result become disinterested in reading, and can quickly become discouraged.  Here are some practical tips for encouraging reluctant readers:
 
• Find books with cartoons or humor  -- which only a child would find amusing
 
Not everything needs to be a learning lesson.  Letting children read books such as Captain Underpants or Diary of a Wimpy Kid will keep them engaged and entertained.  Although adults might find the language and humor distasteful, children find it very funny and are therefore more motivated to read.
 
• Zero in on your child’s passions and choose books and magazines focused on areas of interest
 
Find books on specific topics to keep your child’s interest, such as science, baseball, American Girl dolls, etc.  Children who already have the background knowledge, language and vocabulary before beginning a book will have an easier time getting through the reading.  Order a magazine subscription to Sports Illustrated for Kids or Nickelodeon.  Children love receiving mail and reading ‘their’ magazines.
 
• Get your child an email account and, together, check it regularly
 
Using the computer to read and write is a huge advantage for most students.  By letting young children write and send email, they practice reading, writing and spelling.  Teach your child how to use spell check before sending off messages. Be sure to monitor your child’s ‘pen pals’ – who is your child writing to and receiving mail from? Let your child pick out a few family members, including grandparents and maybe two or three friends.  You will find that by using email regularly, your child becomes very strong in typing (keyboarding) and using the computer.
 
• Find an author that your child likes and stick with it
 
If your child loves reading Hank Zipzer by Henry Winkler or Tales of a Fourth Grade Nothing by Judy Blume, then you have found a writing style which stimulates your child’s interest.  Go through the entire series.  Don’t worry if the reading is below grade level: your child is reading for pleasure and for practice.  Also remember, just because you loved a certain author or series when you were a kid, this doesn’t mean your child will love the same books you did.  Browse the bookstore or library and find the newest, most modern series.  Usually these books contain language and themes to motivate the most reluctant reader.  Kids need to relate to what they are reading, and modern language usage helps.
 
• Let your child talk to you about the book they are reading.
 
When we adults read books we enjoy, we like to talk about them.  After reading a book, we don’t necessarily want to write a summary, book report or make a project of it.  We just want to discuss it with someone else.   Look interested in what your child is reading (yes, even if it is Captain Underpants) and ask questions and have your child tell you about it.  Laugh with your child about the funny parts (even at the bathroom jokes) and help your child feel good about reading.

take him to the library and when he finds a book that he likes and make him read the first 5 pages.

I struggled with the desire to read when I was younger.  My suggestion is to write down his accomplishments as they are accomplished.  Write down every book as he finishes them.  Or write down a book that is started and then have him put a sticker by it when it's down. (Even my 13-year-old loves stickers) Maybe when he sees what he can do, he will have more confidence in himself.  
Also, reward systems work wonders.  I have four children of my own, and I have two who read constantly and one who is not really interested (and one isn't old enough).  But, with the one who is not interested, we have a "secret reward".  If she reads a certain amount, she gets different rewards.  Sometimes she wants "special time" which is time spent with just me to color or play dolls...something she chooses and only with her and I.  Or her reward could be something small from the store for a $1 or $2 that she works toward.
But, as someone else mentioned, don't force it.  It could backfire and he will hate it for a long time.  So make it fun!

Hi Lucygeorge
my son was also a reluctant reader. I had the same issue with crying when asking him to read a book, although he loved to hear me read to him.
I started by just getting him to fill in a missing word as I read, then taking it in turns to read a sentence, then a page etc. For me non-fiction books were what he was most interested in.
I also used other resources such as asking him to help me read a recipe for brownies, read game instructions, played on educational games on the internet, or read other things like magazines rather than just books.
His reluctance drove me to start my own kids publishing company where reading can be fun because you read on the computer. The illustrations come to life through animation, the story can be read to the child whilst the words highlight [modeling fluency], or a child can read to themselves and click on any unfamiliar words to hear them spoken. When my son was younger I struggled to find quality books online that were engaging and fun. He helped me to shape what a child wants from books. When reading is fun then they want to do more of it.
Good luck with his reading, I'm sure if you are relaxed about it yet keep the importance of reading high on the agenda you will soon develop a literacy lover!