Had sex and it felt like my vagina got tighter now my vagina is red ad sore and burns and is itchy boyfriend is clean. On my period. Yest infection?

Start there. It is not an unreasonable thought, particularly with the red & itchy components. Can try otc yeast treatment (i never recommend the 1-day options, as too many fail, 3/5/7 have better success). If resolves, then done. If not, then get checked by gyn.