Sharp cramp like pain run from butt to foot on left leg when standin up from sitting down last only for few seconds then goes away?

Back ; leg pain: James, this may be a pinched nerve in your lumbar spine. The cause is most likly a damaged disc. Please get a proper examination and evaluation. In the mean time, please do not lift heavy items. Also when you are sitting, it is more harmful to lean forward causing more disc damage. Prolonged sitting is unadvisable. Avoid bending forward such as in tying shoe laces, picking up objects etc. Good luc.