I am not DLD but i should tell you this dude, anytime there is pain, STOP. Re-evaluate your routine and technique, look for spots, look for burst blood vessils, look for hard lumps or scar tissue.
Any of these conditions may range from Nevermind, it's only a result of an unusually intense session to DAIUM I FUCKED UP. Take it easy and stop all exercises for at least a week and then try it again and see if pain is still there. If it still is then something may be "broken", if not...go ahead as usual.
Warm up VERY WELL ALWAYS, do not go overboard on the intensity, it should be unconfortable but NEVER painfull.
Usually a dull ache is only soreness, lactic acid buildup and just plain old lack of conditionement. A sharp pain is a much different matter, usually it is something more serious like nerve damage or torn ligaments or tendons.
Stay safe,
Peace
Mike