The day after intercourse and 3days before my expected period i started to spot day2 its heavier can this be implantation.my boobs hve been sore 2wks?

Absolutely not .: Implantation bleeding is a very small amount of bleeding a spot or two spots of bleeding and according to some doctors implantation bleeding even do not exist , it is an internet myth. Coming to your boobs being sore , that is part of the process of preparing woman for a pregnancy , it is due to hormonal changes in the reproductive system. If pregnanyc does not happen pain gradually goes away.