I have been throwing up and nauseous. My OBGYN set up for an ultrasound tomorrow to check 2 lumps on my left Breast and also look for inflammatoryBreast Cancer. I'm 26 with no kids or preg. I've gained a lot of weight and have stretch marks on breast?

See below. I'm not certain what your question is? Breast cancer at your age is very uncommon unless you inherited a cancer causing gene like BRCA1 or 2. Nausea and vomiting can be due to worry/anxiety regards the breast lumps, among other causes. Slow deep breathing can relieve nausea: inhale thru nose, exhale thru mouth. Ginger Ale or Ginger Tea may help. Hopefully your ultrasound will be normal!
Stretch marks are. common with increase in weight, especially increase in breast size, but one would not expect nausea and vomiting to be associated with your breast lumps. It is good that you are getting those checked out with ultrasound, and hopefully they will be not be cancer. If you are having headaches along with the n and v, or if the stretch marks are more generalized, this needs further evaluation.