I would say work with your pharmacist and Medical Oncologist. Sadly our General Practitioners are badly versed on drug, food or other supplement interactions.

I would make a list of all vitamin supplements, Over the Counter Meds, Prescriptions and food that you eat or drink as I'll bet we find the culprit somewhere there.

I don't recommend not taking pain medications if you need them as pain is the enemy of healing. It puts the body in distress slowing or stopping the healing process due to hormone response so if you need to take it by all means, don't try to "tough it out". I would take a look at your dosages first though, if you are taking them on an empty stomach etc or getting enough water as hydration/nutrition is important there too.

the more details you give the faster we can get this thing solved for you.