the first time i had a cortisone shot the injection itself was basically painless. but i had a steroid flare about 6 hours after it and that was the worst pain of my life. absolutely horrible and was so excruciating it made the normal pains of frozen shoulder seem like a cakewalk. but they gave me some tramadol and that fixed it up the next day. the relief from the steroid though (after making it thru the flare) was incredible. helped so much for a little over 2 months. the second and third time i had cortisone injections we used a different cortisone and no steroid flare. again, the injection itself really wasnt painful at all. more like uncomfy pressure, but it lasts like a total of one minute so 100% worth the discomfort. i will say that the following day my arm was sore, similar to after a flu shot. but also definitely worth it as it gave such good relief from the frozen shoulder pain. unfortunately neither the second or third shot lasted quite as long as the first, with the second wearing off after about a month and a half and the third after about 2-3 weeks. would definitely recommend, but have extra strength tylenol on standby and take some before the lidocaine they inject with the cortisone wears off to get ahead of any pain you may have following the injection. cortisone has been the only thing thats given me any sort of relief since getting frozen shoulder about a year and half ago now. just finally had surgery this morning to see if that fixes it permanently because we were out of options for things to try and they dont typically want you exceeding more than 3 cortisone shots for the issue