Left Longissimus, Spinalis Thoracis muscles enlarged

Patient: So it all started when I noticed/felt swelling on the left longissimus or Spinalus Thoracis. Felt like a bump almost. Roughly 9 months later I started experiencing severe nerve pain in my left leg. Finally saw a Doc and I’m told I have a crushed disc which leaked fluid and pinched my left sciatic nerve. Over time the extreme pain in my leg went away but the swelling/lump in my back muscle never did. Is this normal? They say my muscles are compensating for the weak disk. All that being said, is there any way I can work out my right side only because the swelling has been causing me extreme discomfort for the last 2 years… Please help me if you can I will be forever greatful..Thank you,Alain Tasse

Symptoms: Mid back pain