Can pain meds after surgery normally cause nausea and no appetite?

Yes and Possible: Most narcotics used for moderate to severe post op pain can cause nausea. You may lose your appetite due to a decreased gut motility, and your pain. So, i'd only use the narcotics when absolutely necessary. I'd try an anti inflammatory compound , if ok with your surgeon, such as Ibuprofen and naproxen. Also, topical comfort of a wound can be achieved by ice initially , then heat. Good luck.