What Causes Redness And Swelling In My Left Foot?

Thank you, yes my question is for several weeks my left foot is swolen, redish and sometime hot to the touch. I have a hard time walking so I am limping and causing my other leg to hurt.I had xray and no break or cracks so I have appt to go to a foot dr,. My question is can a blood clot in the leg cause this. I am worried about that.
Thank you
Deloris