Lump/other symptoms and heading into diagnostics

Hi, New here and first post. I am a 40 year old mother of one. This past week I found a breast lump (really by accident) in my left breast, upper outer quadrant. It was very noticible to the touch and I had my husband feel it too and he also felt it right away. It is hard and not really moveable (seemed attached to the chest muscle). The next day -- very worried and after I looked up info on lumps (I know, I know Dr. Google is never a good idea!) -- I did a fuller self-breast check and noticed that my underarm on the same side had noticibly swollen glands as compared to the other side and that there was puckering/dimples underneath the left breast. Suffice it to say, I was paniced and was able to make an appt at my GYN's office the next day (yesterday) where I saw the very wonderful NP.

She also felt it right away and noticed the swelling under the arm too. She called and got me an appointment for a diagnostic mammagram this upcoming week at a radiologist group (where she said that she thinks they may also want to schedule an MRI too ... and she said that she will be able to get the results very quickly and call me at the latest the following morning). She also told me to go ahead a call a breast surgeon she recommended and tell them that she said she will be sending the imaging over right away and to get me an appointment regardless of the radiologist's findings for a second opinion and that she may want to schedule a biopsy.

I know that no one can say whether this "sounds bad" because there are always many possibilities until all test results are in, but I am understandably very nervous. I am very grateful that the NP was so thorough and quick to get the diagnostic process moving along speedily, but her urgency also has me thinking the worst. Anyone have any particular thoughts here?

As background, I do not have any family history of breast cancer ... I do have autoimmune conditions. One other maybe random or unrelated symptom I mentioned to the NP was that in my left hand (fingertips) I had been having very sore/throbbing "nervy" pain on and off for the past month. Just a week before, I was going to make an appt about it with my PCP, but since it disappeared, I figured it was maybe a pinched nerve or something and would go away completely soon. Yesterday it returned.

Thsnks for he read, and I appreciate any thoughts. Best to everyone here in the stressful wait time.