A pulled muscle

After having acute back pain last year that went away thanks to Dr. Sarno, I have developed an allergy-probably astmah (TMS?). Also, over the past year I have suffered from back pain but not acute like last year.
Recently I pulled a calf muscle (the Dr's diagnosis) after walking on a treadmill for an hour. Finally after a month it's almost better.
I feel that I need physiotherapy to continue walking and exercising although Dr Sarno writes not to. How am I supposed to know if I'm overdoing it as far as my leg is concerned? This is connected to TMS!!!???