Muscle imbalance. From a doctor.

My left arm (shoulder, bicep, forearm) is weak as compare to right side. Right arm is lil fatty than left. I started gym before 2 yrs, i did the the exercises with very poor form, no calculations of sets and reps (because oflack of awareness) thats why it could be happened. At that time i also had lil difference but now its increasing (not much but noticeable). I leaved the gym after 5-6 months. But my left arm is now very weak. I have come to know that it could be due to scoliosis or atlas (c1) misalignment. What should i do to equalise my both side. I have a special split to equalise my both side(given by professional nutritionist) but before start workout i want to know the suggestion from a doctor.