Took bra off, right breast slightly larger, red streaks, areola nipple sore, sometimes burning slightly red under breast. Is this cancer? I'm 51

See a doctor. Sounds like an infection, however, if this has been going on for a long time, cancer should be considered. Please see a doctor in the morning.
Not likely. With that said, breast pain and redness of the breast can be associated with cancer. More commonly this is associated with mastitis (infection of the breast). You should see a doctor and have a mammogram.