Well, back pain is one side effect I DIDN'T have. Started with the expected pounding heart and head rushes, which I handled with doing the shot and going to bed. Had a moderate headache 24/7 for a while. Then we had middle of the night vomiting, which lasted for only a few nights. Next up came the leg aches (6 or7 level on a pain scale) every afternoon and evening. But the worst of all was nearly total exhaustion, which set in at around a month on the drug, from afternoon on. Endo doc suggested I try partial dosing , but by then I'd had enough of Tymlos, so I quit. Felt like myself again two days later. On Forteo now for about 5 weeks, and doing fairly well , which surprises me since the two drugs are very similar. These are powerful drugs, and it's hard to predict how each human will react.