What Is The Pain In My Arms After All The Lymph Nodes Removed?

I had breast cancer 18 months ago and had all my lymph nodes removed in my right arm, yesterday I started to get pain in my hand and today in my arm, it feels as though the pain is in my actual bone. My cancer was oestrogen based so I am being forced into the menopause and as a consequence no longer make that hormone. A scan has shown no signs of oesteoporosis (I'm 40)...any ideas????