Hi, my husband has this. He got it after tearing the cartalage in his sternum and ribs by holding a several hundred pound trani on his shoulders while doing the job. His sternum has actually sunken in when he's laying on his side and he has to throw his arms back to pop it out and it's almost enough to floor him.
It's extremely painful and they said there was really no cure, just that he needs to quit being a mechanic....not gonna happen.
My best advice is to do some type of physical therapy with someone who is skilled in this because you can do more damage than good if done wrong. Also, my friend who is an EMT said that it's possible during CPR to cave his chest in. I don't know if it's only while it's flaring up, but may be something to look in to. You shouldn't kill yourself with the worry over this, this is just something that I came across.
Also, anti-inflammitories are helpful with the swelling/inflamation in the cartlage...just don't do what my hubby did and take them just whenever....keep on a schedule and don't go days between doses. Also, hydrotherapy/water aerobics may be helpful in building more muscle around the area to support the strained areas.
My friend also does massage therapy and has worked on my hips....one side of my pelvis is dropped and causes excruciating pain, but she stabilized the muscles around my hips to allow my ligaments a little more relief. They had become stretched out over time and the muscles were trying to compensate and in turn, made the damage worse because they had no business doing the jobs they were trying to do.
His has since eased up considerably, but he went through a phase where he was in constant pain and if he got a chest cold, forget it....he was miserable!
So, take care not to do things that may strain that area....especially lifting and certain twisting...look up proper body mechanics and use them. You may also find that using a 12" wide ace-type bandage, wrapped snuggly around your chest will help. Just don't use it for the long-haul as it may decrease the muscles ability to stabilize because their job is being done for them.
Use it when in pain or doing things that aggrivate it and if sleeping on your side seems to aggrivate it...STOP!!! LOL If it hurts, don't do it....wise words from my doc grandpa. The only thing that you should never stop doing if it hurts is breathe...other than that, if it's not necessary to living....doesn't need to be done.
I know you're worried and scared, but if it will ease up in my hubby's case...who's pig-headed and never listens to a doc or takes prescribed meds or advice, if you do even 1/2 of what you're told, you should do much better.
Good luck.