Can pain or tetanus shots elevate glucose levels? My son recently had both and his levels have been high.

Any stress a problem. The normal response of the body to any stressor include the output of Epinephrine & cortisol . The amount will be in proportion to the stressor;physical trauma(shot, fall, illness) or mental(fear). These chemical agents will push up the blood sugar thru a variety of metabolic effects.
See below. Both pain and shots ca cause a temporary increase in blood sugar levels. However, it is usually short lived. If the blood sugar levels continue to be elevated then consult your physician.