I Have Been Experiencing Severe Pain In My Arms. They

I have been experiencing severe pain in my arms. They keep getting weaker and weaker. Last night I got up to go to the bathroom and I couldn't even pull down my pants. My arms just wouldn't work. I have been going into my doctor the last year for this problem as it has been getting worse. She has me on gabapentin 600 mg in the morning 300 mg afternoon and 600mg at bed along with Norco 10/325 2 every 6 hrs with advil. Nothing is working. There are times I go to grab something and it just falls out of my hand. What is going on??