Back pain and codeine

Am

I've been struggling with back pain around my bra strap area for months now, due to pregnancy. Have had numerous massages, stretching routines, heat packs, cold packs, new bras, new pillows and physio appointments but nothing has worked. I work in ICU so I'm uo and about for 12 hours a day and can't really rest as much as I'd like. Spoken to the gp numerous times and he said if it doesn't improve he may prescribe codeine, has anyone else taken this during pregnancy? Did you feel this was safe and helped? Thank you 😊