You can still see a doctor or a vet...but you (your parents) need to call ahead. The only safe pain relief will have to come from a vet...giving him ANY kind of over-the-
counter medication (normally used for people or even for other pets) will be toxic & probably kill him. Sorry, but you'd need a vet for this. If the problem is ingested
aspen, you won't be able to see the blockage, assuming there is one (?).

Any chance his activity is NOT pain, but wanting out of his cage, either to breed or because it's too hot, for example? What are his cage temps? what is his set-up?
Post pics if you can.