Hi Pam
Panting is can be a very non-specific sign of discomfort or a metabolic problem. (A metabolic problem can mean something like diabetes, kidney disease etc). So typically a very good examination is needed, including mouth and belly (pushing on organs inside) to see if one can find any areas that are tender. Because aspirin seems to help, it could mean something is uncomfortable and the aspirin helps relieve it.

If no areas are clearly tender, which can sometimes be very hard to find, then it may be good to run blood and urine tests. This will help rule out that there is underlying metaolic disease or a urinary disease. Urinary bladder diseas can also cause discomfort, so it is good to check too.

So at this stage, you may have to check a bit at a time until you can sort out where the discomfort is. A bood and urine test can really help rule a lot of internal problems.

I hope this helps give some ideas to pursue. Please keep me updated.

Evan