TNBC: Pain in armpit, how do I ensure it's not cancer coming back?

Hello,
I am 4 months out of surgery double mastectomy and sentinel dissection (23 lymph nodes removed)
I went to lymph PT after 30 days and the cording issue was what we work in regularly.
Many at home exercises and massaging the cords during PT.
The Mayo PT specializes with breast cancer so understands the limitations and also educates along the way on lymphedema.
I will continue for another couple of months.
I feel better after every appt.
But, I also understand I will have some type of long term issues.
All good - hope you release your pain.

The pain comes and goes and I haven’t noticed any swelling. The tenderness is always there.

There are a lot of great ideas here! I would like to add one more. Because you have had a lymph node dissection, you do have a higher risk for local inflammation under your arm. I now get a sore inflamed lymph node under my arm every time I have a little allergy. I also get a little lymphedema pretty often.
Is this tenderness constant or does it come and go? Is there swelling? Final question, lol, does anything make it better?

There is also something called lymphatic cording. Thin little cords form and pull. Most doctors do not know what it is and some PT clinics don’t know because they don’t have a specialist in lymphedema or breast cancer. I went to a PT lymphedema specialist in the hospital as an outpatient. They said they had to break up scar tissue and that I had a lot more “cording” than I realized. Lots of exercise involved. Hope it’s as simple as that and be persistent about being evaluated for lymphatic cording. It’s a real thing.

I am 9 year survivor and have experienced the same pain on armpit that I attribute to lymphedema. I had lymph nodes removed and radiation after surgery. It usually flares up when o use my arm a lot and hot weather aggravates it. Massaging the area very lightly will help . I attended a lymphedema clinic when I first experienced this and it helped immensely. Sometimes I wear a compression camisole that helps displace the lymph fluid build up.

Im feeling the same and I had lymph removal only in my left breast but both are sore and its been over a year since surgery