An acupuncture needle is almost as thin as a single strand of hair.  Because of this, most of the time the insertion of an acupuncture needle is painless.  Although sometimes the patient might feel a pinching or pricking sensation.  However, once the needle is in the body, the acupuncturist might choose to stimulate the point.  Here the sensation might feel heavy, achy or throbbing.  This doesn't last long and soon the body acclimates to the needle and the sensation leaves.  You must always let your acupuncturist know if the needle is too uncomfortable and it will be readjusted.  

After an acupuncture treatment, the muscles might feel tired or sore, like after a good workout. This is normal and should get better within a couple of days.  It is very important to drink lots of water during this time as the hydration will help ease the soreness.