I have groin pain walking, sitting, climbing stairs & wakens me at night, what could be causing it?

Could be Hip or...: Pain laterally & upper thigh where you would think of your hip joint being can be bursitis of the hip. Aching deep groin pain can be a pblm w/ the ball & socket of the hip joint on that side. You would also think of a lower abdomen/groin hernia, or a strained muscle with an attachment in the groin, of which there are many. Start w a physical exam (hernia) and progress to xray of the pelvis/hip.