LIFE...AND THE THINGS IT BRINGS

THIS IS WRITTEN BY THE NETDOCTOR MEDICAL TEAM.  TO ME, THIS IS A VERY TRUSTWORTHY SOURCE.
I HAVE BEEN EXPERIENCING THESE STRANGE PAINS AND THEY SEEM TO BE GROWING. THIS IS A GOOD THING TO KEEP IN MIND.
WE ALL NEED TO PAY ATTENTION, WHEN OUR BODY IS IN PAIN... IT IS TELLING US, "THERE IS SOMETHING WRONG"

Intercostals myalgia. It is not a serious condition, but it is a nuisance.
Sometimes it is caused by a viral infection of the muscles, sometimes by repetitive activity or a strain, but often there is no particular cause.
It is usually self-limiting, and goes away on its own, eventually. I must say you have had it for longer than normal, so it might be time to go and speak to your doctor again, as some anti-inflammatory treatment, ultrasound or physiotherapy may help it to settle down.
There are other possibilities, such as a trapped or damaged nerve and if there is local tenderness near the front of your chest, it could be due to inflammation of the joint between the end of a rib and the breastbone.
This is called costochondritis, and has similar causes to intercostals myalgia.
None of these things are serious, so I think you can be reassured about that. But if you find it continues to be troublesome, do go and discuss it with your GP again.
Yours sincerely
The NetDoctor Medical Team