My husband is having a lot of pain on his left leg near the bend of his hip. What could this be and should he go see his regular dr or a chiropractor?

See doctor. Pain in the hip may indicate primary hip problem or even issues with the knee or ankle.
Various. This could be a local problem aggravated by leg motion, or referred pain from nervous dysfunction, or sciatica or some pelvic disorder. This should be evaluated by a regular doctor. Do not waste your time and money on a chiropractor who cannot make a diagnosis but will offer a series of deep massages with no cure.