Pins and needles with hypersensitivity (allodynia= pain to non-painful stimuli like touch or hyperalgesia= pain out of proportion to painful stimuli like sharp) all indicate the you are experiencing neuropathic pain (pain from the nerve). Neuropathic pain comes from a damaged, irritated, or dysfunctional nerve. As an analogy, seizures are caused by nerve damage or dysfunction that sends abnormal impulses through the nerve that cause movement. Sometimes abnormal impulses from faulty wiring causes pain instead of movement. That is why anti-seizure medications work to relieve nerve pain.

Your leg pain started in the peripheral nerve after the trauma. Over time, this can lead to central sensitization in the spinal cord and brain. Usually, this central sensitization causes nerve pain to intensify or spread. Spread in which direction? Sometimes upstream towards the body (like foot to thigh) or sometimes to the opposite side (like left to right). Spread to a remote location (leg to shoulder) is less likely, so an examination of your neck and shoulder by your doctor is recommended.

Referred pain is different than nerve pain. Referred pain is usually a diffuse dull ache without numbness or tingling.

If you want a great book to read about pain, I strongly recommend "Explain Pain" by David Butler (available at www.optp.com). 

Dr. Christina Lasich, MD