Infection anywhere in the head can cause sensitive scalp and scalp pain. Even a common cold can cause bouts of scalp pain.
Clean up your dentalware and environment. Lumps on the scalp are often called sebaceous cysts, actually this is where your body has sequestered PCBs (polychlorinated biphenyls, extremely hazardous, now banned in the U.S., but often a pollutant in detergents.) Get rid of them by switching off detergents for all purposes. See Recipes for dishwasher liquid, dishwasher detergent, and laundry detergent replacements.