I am a 58 YO female, 50 lbs over weight, work out with a trainer 2 a week ( and I mean really work out, break a sweat), semi active, gardening, walking, work full time. over the weekend I started getting a pain in my back on the left side, right below my bra line, three inches from spine. I don t remember doing anything specific to strain or pull a muscle over the weekend. It really hurts, doesn t keep me awake at night but bothers that I don t know what it is. When I sit in the car is especially sore because I guess the seat tilts back. No problems, breathing, urinating, no fever, no rash, etc.