Anjia - about 12 hours ago you said you are "scared to death" having heard of people getting breast soreness and then invasive breast cancer. You've had a clear mammogram in the past 3 months which is encouraging. However, not all types of breast cancer are readily visible on a mammogram e.g. some lobular cancers, or indeed palpable, so...
...if your feelings of being scared to death have been alleviated by the replies you've received to this thread, all well and good, if not, your idea of a visit to your GP sounds like a good one.
Best wishes.