I need help!!! TMI: breast talk

Okay my boobs are killing me and I can’t tell if it’s PMS or early pregnancy. I’m not sure what DPO I’m at but it started about 4 days ago. It is now roughly a week before my period is supposed to come. My boobs and nipples feel super sore and extra vainy. Does this seem like PMS or an Early pregnancy sign? I’ve also had a cramp like feeling on my right side. If I need to I will post a picture.. it hurts to even walk with them things on my chest