Muscle in breast?

I’ve just seen a training GP, I’ve mentioned training as where I have noticed a change, a hard area under the skin she said she couldn’t feel it. I can only feel it when I am sat up and press gently. She was pressing very hard whilst I was lay down and said she felt nothing. I explained how I can only feel when sat up and she said oh that’s just muscle when she felt it as I was sitting up, she wasn’t pressing hard when I was sat up so definitely not the chest wall and she must have felt something to say muscle. I am utterly devastated to have not been taken seriously. I suffer from anxiety so have a feeling she is just putting it down to me on being over cautious as I am on hrt due to a hysterectomy 3 years ago at age 37. Please can someone confirm if she would have been able to feel muscle? The lump is at the side if my nipple not deep inside. 


She was only interested in what it felt like when I was lay down with arms raised. She said they check both ways as it must be felt when lay with arms raised for it to be something. That’s not right is it? Whatever it is I feel it all the time and it appears to be more noticeable. Why can I feel it but she cant, yet she must have felt something. I also noticed a small lump ar 12 o’clock between breast and collarbone, she said that was just tissue. My right side doesn’t feel like that, again she felt it as it was ‘just’ tissue! How can she be so sure?