Marie, cysts and clogged ducts can be painful and do often resolve on their own without medical intervention, so a two-week wait seems reasonable if this is a new development.  Painful lumps are not usually cancer.  If you have had the symptom for months and have just gotten around to checking with the doctor, then you probably need to push for an earlier sonogram.  You are the only person who knows your tolerance for uncertainty.  If you are going to worry yourself sick about this, considered calling back and asking for an earlier sonogram.  If the lump gets bigger or if you develop new symptoms like a fever, redness, or swelling, call immediately.  A fever could be a sign of infection.  Redness and swelling can also indicate a fever or a type of cancer called inflammatory breast cancer.  I hope the ibuprofen and Vitamin E do the trick.