My right forearm aches when i hold it in any position above 90 degrees, like when typing or driving or eating. the ache diminishes if i let it hang. it feels like lack of blood flow when it aches.

Nerve compression: An ache in the forearm whenever the arm is elevated above 90 degrees, and which is relieved when the arm hangs down, may possibly be caused by a Thorasic Outlet Syndrome. The cervical nerves and blood vessels that go to your arm pass thru your neck muscles and then pass between your collar bone and first rib to reach your arm. Several conditions can cause pressure on this neurovascular bundle.