Hi, I found a very good chiropracter and that helped more than flexirl. A good chiro takes x-rays first before they touch you. Also a massage , especially a sports massage helps. Also an ice pack.
You described my muscle spasms to a T
I think it could be sx from the meds, I had also a lot of weird pain in the back and also in other parts some months after tx but its much better now I´m 1 year post!!
Chiro helped me immensely too it does sound like muscle spasms which are the most painful things! I would definitely advise trying one if you haven't yet. Between the doc and a heating pad that was all I really needed to feel MUCH better.
I'm a big fan of good massage. Try yelp to find one near you. Look for someone specializing in therapeutic massage.
Therapeutic massage can be great. I hope it helps.