What over-the-counter vitamin or supplement can help with back spasms?

No supplements . There r no supplements but rest heat pillows under knees even lying on the floor with butt close 2 the couch and legs up on the couch. That & otc nsaids if u r able 2 take them. This is 4 the short term 2 get u thru a wk end or until u can c ur pcp or orthopedic surgeon.