Re: medicine for pain for minor surgery

Analgesics (the drugs you mentioned) are effective for reducing pain. Anesthetics (such as a local anesthetic) prevent the transmission of sensation or feeling and therefore also act as analgesics.

An analagesic would not be sufficient to prevent you (or your body) from reacting to the painful procedure. This reaction, beyond the psychological distress, also evokes a number of physiological changes including increased heart rate, blood pressure, etc., that could be problematic.

Muscle biopsy often requires more than a single needle biopsy to be taken and sometimes use an open biopsy approach (making a small incision.) The pain involved would be significant and not sufficiently masked by an analgesic.