Weight gain, in the short term, is rarely the cause of pain but instead, often exacerbates existing problems. The weight we gain causes more force on the joints and muscles and can lead to weaker or improper functioning areas to become painful.
It is advised to consult an evidence-based chiropractor to help better determine the cause of your pain and find an appropriate solution. Here is a link to a group of evidence-based chiropractors around the world. http://www.forwardthinkingchiro.com/member-map-1/#!map