Thanks @veenaga and welcome to the forum! Feel free to tell us your BC story so far in 'Newly Diagnosed' category. :) ...
Yep, I'd had the cortisone injections into both my shoulders over the years prior to my procedures being carried out - but cortisone only relieves the symptoms - it doesn't 'fix the actual problem/injury' that caused the bursitis. And you are also limited in the number of cortisone shots that you can have in the one area. :( Sometimes, only allowed the one!
Bursitis is a fluid filled sac that develops after an injury, to protect the surrounding area (usually between the bone & a tendon.) It can be drained (if done early in the piece) but if left too late (being regional, mine took time to get all the XRay/scans done that proved the bursitis was caused by an injury) then it can become thick like custard & then it can't be suctioned out by a needle (which happened to me.) :( If the inflammation doesn't go down after the cortisone shot, it is usually an indication that surgery may be required due to torn tendons, or actual impingement of the shoulder.
The shoulder is pretty well the most complicated set of bones, tendons & muscles/ligaments in the entire body - and if just one of them is damaged, torn or chipped, it needs to be addressed fairly quickly - often with surgery - as otherwise it will just continue to get worse.
If you find that your shoulder is restricting your arm movement (eg you can't do your bra up behind your back, or can't reach up & wash your hair ..... or can't lift your arm higher than horizontal - that is the time you need to see a shoulder specialist - usually a surgeon.
take care
