I am a weight lifter, am i possibly at more risk for thoracic outlet syndrome?

Possibly!: Compression of nerves and blood vessels can be caused by an extra cervical rib (above the first rib) or an abnormal tight band of tissue connecting the spinal vertebra to the rib. Many patients have injured the area in the past or overused the shoulder. Increased muscle mass can increase the chances of thoracic outlet syndrome. On the other hand, appropriate physical therapy may help relieve it.

Perhaps: Since tos involves compression of the lower brachial plexus next to the neck or even more distally over the lateral chest wall, any structural problem, such as a cervical rib or an elongated transverse process, or an aberrant ligament could cause symptoms secondary to various traumata. Overhead, or military press maneuvers seem to increase these compressions.