Consent is not a blanket concept when it comes to sex. It has moved away from no means no to yes means yes. Specifically this means that even if you hadn't said no, if you hadn't specifically said yes, then you haven't consented.
In the situation you describe, anything unexpected, unwanted and objected to is assault.
To try and be a bit more specific, for example, I am in a long term relationship. I have had sex with my husband many, many times. I have a slight kink for being held still. Just because I consented to that last week, doesn't mean I consent to it tonight. I can consent to kissing and oral but say no to penetration. I can say yes to piv but no to anal. I can say yes to Piv and no to oral. Or whatever combination I want (and don't) at any given time. DH cannot assume that because I kiss him he can have more. He cannot assume that because I said yes to something a month ago, that I am consenting today.
Consent is fluid, but in your case, appears (to us) quite straight forward. You consented to something, the person you were with did something else that you didn't consent to. You made it clear that it hurt and explicitly asked them to stop and they didn't. There is nothing vague in that, it was assault. Sorry OP 