I am experiencing hip pain (lower right side) and bruising but the bruising is yellowish and my husband says it looks old. It certainly hurts to lay on. I don't remember hurting myself to cause such pain.?

Likely old. It is likely you injured your hip without realizing it. As a bruise progresses from initial deep purple color from traumatized blood vessels under your skin, your body slowly absorbs the blood, and the bruise changes colors - light purple, green, yellow as it fades. If you're still having pain, you may have trochanteric bursitis, and may benefit from a steroid injection.