When i raise my arms i feel a tightening on the left side of my chest them feel dizzy. now my left arm has been tingling. i'm not sure what causes

Tightness: There may be tightness of muscles and/or ligaments that crimp nerves and/or circulation going to and from the arm at an area in the upper chest, called the 'thoracic outlet.' rarely, this can also affect circulation to the head, a condition called 'subclavian steal.' occasionally the first rib and collarbone are too close & do the same thing. Rarely a tumor high in the lung can contribute.