When you say fibro pain in chest can you please describe that? Are you having a bump, lump, focal pain or nipple discharge? Have you had a screening mammogram that suggested a diagnostic mammogram?
I want to answer the question I think you are asking. Mammography is a highly regulated imaging service. 2D and 3D mammography is the gold standard for breast imaging. Your doctor may consult with a radiologist to determine if an ultrasound can be done. This is normally limited to something like a swollen lymph node in the axilla. However, an ultrasound does not replace mammography, and the radiologists license is on the line. Mammography picks up cancer before they can be seen on ultrasound. If you are called back for a diagnostic mammogram, after a screening mammogram, the tech will take additional images. These images guide the radiologist. For example they would know to look at 12 o'clock 3mm from the nipple. So ultrasound is a supplemental diagnostic tool for mammography, but does not replace a mammogram. If you have had a painful mammography experience, you need to let your tech know. They can move slowly with compression and most people do well. You have the right to ask the tech to stop at any point. I hope this helps.
Have you ever had a 3 D mammogram? These are pretty awesome and give such a full picture that they can show YOU as well right on the spot. Have you had this? I guess they are denying giving you an ultrasound because your mammography doesn't warrant it? There is nothing they see to need to investigate through ultrasound? That sounds like maybe they don't have a reason to put it as a need through insurance. You could probably pay for it out of pocket? But right now, with covid, it is hard to get anything extra done.
Your breast pain. Chest pain. Is it cyclic at all? Hormonal related? You are saying fibro. Are you diagnosed with fibromyalgia? They have medications these days that seem to have a good reputation for working. Lyrica and Cymbalta are two that come to mind. Are you being treated by anyone for this?