Had light bleeding/spotting for 3 days with no cramping. been sick with a cold for 2 weeks. sore nipples and neck. had unprotected sex. pregnant?

Without knowing when: you had the light bleeding and the unprotected sex relative to your normal menstrual cycle, I can't tell you the likelihood of pregnancy. However, if the bleeding occurred around the time you would expect a normal period, the results of a home pregnancy test done now could fairly reliably tell if you are pregnant or not. I recommend you do one.