The injury could have caused a sprain.
Sprains are impacts to or overuse of the muscles or the tendons that connect them to the end of the bones.
I don't know how long you've been suffering the pain. If it’s a few weeks than rest interspersed with some mild activity to maintain mobility is the right thing to do.
However, if you've been suffering for a few months and are missing out on your football, it’s very much worth contacting a physiotherapist (to find one, just search physiotherapy online and their governing body will pop up).
I'm wondering if you might have some scar tissue by the symptoms you describe, something only a physical therapist (and perhaps a sports masseur) can address. Try looking at myofascial release. It's basically deep tissue work and involves the therapists elbows and knuckles, but could theoretically reach the part other therapies cannot reach.