The primary objective of this RCT is explore the mechanism for Hemiplegic Shoulder Pain (HSP) reduction due to treatment with peripheral nerve stimulation. We will explore the association of subject-specific clinical and demographic information and pain relief from PNS. We will explore the possible role of central sensitization mechanisms in perpetuating pain via measures of sensory and pain perception. Lastly, we will explore the dose-response association of muscle-contraction from PNS and pain reduction, completion of activities of daily living (ADLs), and improvement in quality of life.