Breast discomfort and pain. On inside?

I feel pain on the outer side of one breast, either constantly for some time or sharp pain for a second anytime during the day. It has become unusually large and deformed on the inner side. It weighs down on the outer side if I lay straight on my back. The nipple looks darker in comparison to that of the other breast. This started 2 years back. I got it checked but no lumps were found back then. I passed it for a consequence of weight loss or gain. But it does not get better. Rather it causes discomfort, pain and doesn't fit the same cup size. The bulging appears distinctly and is easy to spot on top of clothes too. Could it be a cyst or some sign of cancer or any other possibility? Which test do I get done to get an image of what is going on inside? My town does not have specialists or any physicians I could trust with this but I could go to a diagnostics center and share the report online. It is worrying me and I don't want to wait to visit a city nearby after the pandemic ends.