I understand your concern that your symptoms are not being taken seriously, but based on the limited information you have provided, it is difficult to even quess what might be going on. You did not mention your age, what, if any, tests have been done (bloodwork? X-rays? mammogram? ultrasound?), or what, if any, other health conditions you have.
Therefore, the only suggestions I have would be for you to discuss your concerns again with your doctor(s), to make sure you fully understand their assessment of your symptoms, or to seek another opinion if you do not have faith in your current doctors.
The breathing problems are a concern. Go back to them with that as your chief compliant.