Pain in one breast

For the past few months, I've been experiencing a dull pain/heaviness in just my right breast. I also experience the pain in my back and recently my armpit too. Sometimes it feels like only a noteable discomfort and sometimes it is a direct pain, but there is an element of discomfort at all times. I am only 23 years old so don't feel like I'm being taken seriously for my pain when trying to get referred for any kind of diagnosis. My breasts aren't showing any other symptoms but the painful one feels slightly more dense/firm than the other, I feel very worried about it but was wondering if anyone has any advice on what I can do if I can't get through to a GP? Or if anyone with similar symptoms got a diagnosis just so I could possibly get any idea of what is wrong. Thank you :happy: