Blood pressure was taken with cuff to small, then repeated. Ever since I have had severe pain in left arm now seeming to radiate into lower arm. Its been 3 weeks.Used elastic bandages for first week then told to use heating pad. Motrin is not easing pain and I can't lift arm any longer.

I would look at seeing a doctor or maybe even the ER. That is serious. I am hesitant though to link the blood pressure cuff with what is happening with your arm.

Regardless you need someone with professional training to look at it and quickly. If you're getting nerve damage, you need to fix it quickly.

Cuffs are definitely made in different sizes. OP has a valid concern and should follow up any pertinent discomfort.

Oh I know they come in many different sizes. Considering the placement of the nerves in the arm and how the blood pressure cuff works with the stethoscope, it just seemed odd that this would occur. More improbable than anything. I agree though that the cuff could be the cause.

Regardless of whether that is the cause he should, as I said, see a doctor because there is nerve damage occurring and it needs to dealt with by a medical professional.