What type of ankle injury could I have?

i was playing football earlier today and got my ankle injured in a challenge. I carried on for a while but had to come off. it is a bit swollen on the upper bit of my ankle. but there's not a lot of pain and I can walk fine most of the time. however it stiffens up if I don't move it for a while and my foot feels heavy. any idea what this could be? I've had a fracture before on my other ankle but swelling was way more severe and there was a lot more pain.