This also causes heel pain, and because of the posture pain is also felt in hip, knee
, and lower back. This can explain excessive pain on your left side.
This occurs due to weakness of gastrocnemius and soleus muscle, ligament weakness, discrepancy in length of both legs, high arch of foot, tibia varus (inward angle) extending beyond 10 degrees or due to forefoot varus.
Do discuss with your doctor and see if all these possibilities have been looked into. Take care!