Hi ajinlove,
How does he do on reading achievement tests? Is he possibly just too active to want to sit still for long periods of time? (which actually might not be terribly unusual for a 7-year-old boy)? Is there anything he has enjoyed reading in the past? Have you tried the Life of Fred books or Beast Academy (books about math)?
DD's very bright friend was found to have stealth dyslexia at about this age, but unless you are seeing signs, this might not be anything to worry about.
My DYS DS7 is impatient with words in math, but he has been forced to deal with them as the teachers have been giving him quite a few challenging word problems in school. The biggest problem I observe with him is a failure sometimes to CAREFULLY READ the details of the problem. I jokingly read the problem ssslllloooowwwwlllyyy to point out to him that he has missed a crucial detail, despite the fact that his math was otherwise fine (ok, sometimes he doesn't appreciate this). This is the kid who drives me bonkers because he wants to solve everything in his head and sometimes does so correctly, before I am finished working the problem alongside him. Other times, though, he'll simply make a silly mistake this way. He likes to do math QUICKLY.
My DS, I think like yours, almost prefers to do math problems to reading. Despite a very high VCI and very high reading achievement scores (DYS-level reading and math on the WIAT), he cannot seem to plant himself still for as long as DYS DD did at the same age...he is NOT hyper, but quite physically active. Most of his reading occurs at night when he is pretty tired. I plant sports books, the sports section, National Geographic Kids books on topics he likes around the house for him...sometimes it works. He has managed to read some challenging books this year. I don't know that he'll ever read as much as DD did/does, but he is a different child!
Hang in there!