on and off hot sweats from tramadol

hi there everyone, just had a benign dermoid removed via laparoscopy 5 days ago. have made good progress in terms of mobility and appetite, all seem to be progressing well. Am taking tramadol as pain killer meds, but and keep having on-off sweats,of about 10 minutes duration. My skin is physically clammy but then dries and I feel ok, then it sweeps upon me again. Has anyone had this ? is it a side effect or more to do with surgical recovery? thanks