Ouch. Poor little guy. That’s a lot to go through. I don’t think it’s wasting time to check up with a vet - especially if it’s seemingly a source of pain or an area he’s over grooming or scratching. Of course, that’s as long as you’re prepared to pay the fees, accepting the risk to find that he’s just a bit chubbier in that area - but I still think the “it hurts him and he tries to run away” suggests it’s worth checking out if you’re able to.