I would get him checked if you can. It's likely early onset arthritis, but there are other possibilities, like sciatica. But it's best to be sure it isn't one of the more serious possibilities.
stool looks normal. eating a lot. is spayed.
female cat is 7. havent checked stool. Seems to be back related.
is a little sensitive to touching around hips but doesnt seem to be in pain.
I'd need more info. is this an older cat? It could be feline arthritis. If a 6-7 year old (roughly) it could be early onset arthritis due to other circumstances (osteo issue). It could be a constipation issue as mentioned above.
does your cat seem to be in pain? to touch? Does it seem more back or hind leg related? Is this a male or female? how is his stool/urination?
Could be constipated. Could have hopped down wrong from a high surface.