three weeks ago I banged my knee very hard on the sharp edge of a radiator. The pain was acute for a couple of days and I took ibuprofen. A couple of weeks later I did a lot of walking and my knee started to hurt with movement, and also at rest. It has improved since then but still hurts when I walk on it or put weight on it, and sometimes aches at rest. This is three weeks after I banged it, is this normal and should I be resting it or keeping it moving?