Daily hug sufferer here. It is constant for me just not always painful. During a flare it is not fun.
Like Dejibo, I suffered with this long before being diagnosed. However, for me it is my left side and it will feel as though something is ripping, burning, electric shocks, squeezing, and can't get a deep breath. I can only lay down during these painful times which can last up to a week or 2. I have permanent severed nerves due to a spinal lesion and it also effects my stomach. I have no upper abdominal reflexes on my left side.
On a daily basis it is just uncomfortable. I do take Neurontin and that has been a wonder drug for me. It really helps with all the nerve pain and sensitivity not only in the rib cage but all over as well.
I really wish you well in finding a dx, whether it be MS or not. Hang in there and know we are all here to support you on this journey.