Hi Pammy, I had pain down my arm for the first 4 weeks which gradually eased. It felt like bad sunburn inside my arm from elbow to shoulder. I was told this was nerve damage from lymph node removal. Even though it was painful I rubbed a non scented moisturiser into it each day which seemed to de-sensetise it. I was given a lovely soft horseshoe cushion by a breast cancer volunteer to put under my arm and this made a huge difference. I'm just over 4 months post op and am still numb at the back of my arm. (Under my arm was so much more painful than the mastectomy itself!)
Thr numbness has reduced in places or maybe I'm just getting used to it. Keep up your exercises. I started increasing the 4 hourly repetitions from 10 to 20 after the first couple of weeks. I also added a couple of extra stretching exercise of my own depending on where I felt the most tightness. I am now pain free with full arm movement. All the knots and lumpy areas have also gone. I think regularly massaging the scar helped too.
Does your GP or specialist have a physio they can refer you to. They usually have someone who specialises in post op exercise.
I hope you see some improvement soon.
take care, Jane x