Low back pain with right thigh numbness and right arm/hand/wrist pain/numbness. Sneezing causes extreme aching pain in both arms. Thoughts on causes?

Spine specialist W/U. It coulb be from disc disease in your neck or high in the back creating some nerve root irritation from the sudden negative intrathoracic pressure created by the sneeze. When not sneezing the disc may look normal, which makes it very difficult to diagnose. The same phenomenon can result from a build up of bone (osteophytes) near the central canal or the foramen where the nerves travel.
May be more than one. Your bilateral (both)arm pain and numbness sounds like it may be caused by a cervical disc problem. The thigh pain maybe from your lumbar(low back).You need to have further tests from your physician.