Hi and welcome to HCM.
It can be related to your trauma but also It can be subctaneous lesion such as lipoma
. It sounds like tendinits or muscle rupture. All this can be evaluated by ultrasounds because RTG can see only bones. During ultrasound needle biopsy
can be performed if neccessary and then you ll know exact diagnosis. Till that try to rest, apply some cold
compresses, keep your leg elevated and take nonsteroid painkillers. WIsh you good health.