I have foot swelling, minor redness and a good bit of pain when I walk. What can be causing this?

Foot Pain. Typically with foot pain developing you try to analyze the cause. What did I do to get my foot irritated? Then, you try to create a pain free environment to allow healing as much as possible (change shoes, etc). Plus, you begin the classic rice treatment--some rest, some ice, some compression, and some elevation. You can add anti-inflammatory meds or salves. See a doctor if it stuck! dr blake.
More. Info will be helpful to give a moe specific answer. Where is pain? When did it star? Was there any trauma? I agree with advise given so far but these few answers would give more specifics on answer.
Poosibilities. Stress fracture, gout, infection or other injury. See podiatrist for immediate evaluation.