I have a swelling in my ankle , injured last night during a football game , i can walk on it , but it still hurt !?

Ankle Sprain: This is most likely n sprain of one or more of the ligaments in your ankle. Rest it. Ice it. Elevated it. Compress it. At least an ace wrap, a ankle splint if available. Few days of crutches may be needed. Over-the-counter nsaids. Physical therapy and rehab helps more when started early as opposed to later. No football for a while. X-ray, +/- MRI if not improved.

Ankle injury: Even a seemingly low grade injury can have other problems going on. I recommend an exam with a podiatrist to figure it out.