Intramuscular stimulation (IMS) pain relief therapy is facilitated by a hand held tool (1) which once positioned against a patient's skin can be controlled to automatically advance a needle (11) to penetrate the patient's flesh, reciprocate the needle (11) within the patient's flesh a predetermined number of times through a predetermined stroke, and retract the needle (11). A tubular guide member (13) is provided at its distal end with a skin contact member (15) forming a constricted orifice closely matching the diameter of the needle (11). The orifice allows substantially free passage of the needle (11) therethrough, and at the same time prevents bowing of the needle (11) as it is advanced, which is a primary source of patient pain. Automation and control of the needle penetration; reciprocation and retraction sequence reduces the amount of manual, and mental effort required on the part of the treating physician, thereby allowing physicians to perform IMS procedures more consistently effectively and efficiently. This leads to better results (increased pain relief); decreased procedure induced patient pain and tissue trauma; and reduced risk of repetitive strain injury to the treating physician.