Back muscle pain (both side of spine)

I have back muscle pain for past 5 yrs I developed it a few days after I got chickenguneya.i have back muscle pain on both sides of my spine. It has gotten worse for past 1 year I can't even sit for 10 mins and no painkiller has ever reduced my pain. My MRI report says  nothing serious just some muscle tighteness, My doctor said it is Myofascial pain Syndrome He suggested painkillers,Muscle relaxants,Medicine for nerve damage,Exercises & physiotherapy(no effect) and then same medicines & Trigger point injection & exercises I have taken 11 of those injections but still no effect,My pain has only got worse since I started having Injections and did exercises Initially i had pain in sitting only but for past 6 months i started having a lot of pain in laying down as well(I lie in good posture)  .I have tried everything,visited various physiotherapists, various orthopedics but no relief. I have taken various pain killers continuously for past 6 months but they never reduced my pain.