Thanks guys for your replies! I do see the roach back and see the difference in muscle tone. The first picture was taken a little bit after he came off the track so needless to say he was rather fit back then.
I wouldn't be so worried about it but it seemed to just pop up one day after he had a tantrum. Even my friend noticed it. Maybe I never fully noticed it, it's just feels odd.
The vet is coming out monday so ill talk about it with him.