My rt hamstring is very tight, when my leg is straight and there is dorsiflexion of rt foot, i get an intense sharp pain on the outside of my heal (right foot, back of heal at 6 o'clock, pain at 4/5)?

Leg/foot pain: Tight hamstring in that position not too concerning. Probably just a tight "hammy" or mild strain. The heel pain sounds like Achilles tendonitis. Best to have these checked out.

Could be...: Lesion could be lumbar or posterior knee (true sciatic possible, unlikely). Lumbar more probable with tight hamstring. EMG/NCV studies would be helpful. See neurologist.