I’ve had terrible leg pains since start of my illness in 2012. Honestly, no one knows the cause. Always worse after activity (PEM) and also worse when fighting infection. Interferon amplifies the pain. I’m not sure it’s neuropathic. No way to tell if it’s lactic acid build up. Acupuncture sometimes helps but I can’t stick needles in myself everyday (I have tried). I wonder if it’s related to endothelial damage/dysfunction or RBC deformibility issue if they are confirmed in subset of patients. LDN, gabapentin, cymbalta and TCAs didn’t work for me. I’ve tried very hard to avoid chronic opioids. I avoid NSAIDs because I have chronic GERD. I currently take low dose tramadol and acetaminophen daily and monitor my liver and kidney function periodically. For those of us who suffer with chronic pain it really sucks. You have to find what works for you and understand the potential side effects of therapy. I wish someone would invent a new class of non habit forming pain medication with minimal side effects.