Braxton Hicks with pain?

So this is my second but my first was a c section. How exactly do you tell if your having a Braxton Hicks with slight pain or a real contractions? I had a couple real contractions with my first and they killed but every once in a while my stomach tightens and I’ll get a sharp pain in my back just one side the entire time my stomach is tight. Does anyone ever get some pains with their Braxton Hicks? Feel like I don’t count it as a contractions but sometimes I’m unsure lol there is never consistency with them so I’m not even worried I’m just curious what everyone else experiences.