I have had to deal with similar pain down on my left side. Thousands of dollars later the doctors tell me that I'm fine. Still have the pain and it comes and goes. The things that have seem to give me the most relief is yoga, meditation, chiropractic, massage therapy, and the biggest help came from acupuncture. There is a theory out there called micro-tearing. It has not been proven but it is when you have muscle tears so small that no medical devices we have can pick it up. Also, you might want to check for minor spinal problems. Most doctors don't like chiropractic theory about how nerves work but my chiropractor has helped me to improve my asthma through working on my scoliosis. And I have a very minor case to the point where he had to recheck my x-rays to find it. When he did he found a tiny(about the size of a pen tip) bone spur at the joint between the 2 vertebraes. So, when my regular doctors could not find why I had pain in my left side, guess who I went to. So, since then I have used the techniques listed above to get rid of the pain. Massage on my diaphram and acupuncture worked the best and it sounds like you have the same pain just on the other side. And I'm not just saying this because I'm a massage therapist.
I think sometimes medical professionals are so smart that they overthink the smallest things because they are so use to it being something really bad instead of something simple like a pulled muscle. Go to all your doctors appointments first to rule out anything major and then try some alternative medicine. You would be surprisedhow quickly it works.
Thanks very much for your input musiclady. Much appreciated.