Every so often i have qtr inch white bubble looking spots that form under the skin on my arms and legs? any ideas?? never there when i see doc.

Hard to say: Could be urticaria, which is a sometimes fluid-filled rash that happens as an allergic reaction. Many causes for urticaria-- sometimes medication induced, temperature induced, touch-induced, exercise-induced. Self limited and usually harmless. Often responds to antihistamines. Don't really know for certain without seeing the bumps. Best guess for now.