WMc1103
Several aprioris seeem to loom large before considering your problem, firstly ,calling your problem an "injury" ,suggests you are certain there is breakdown in the process of creating pain and altered behaviour of your adductor region. Also that this supposed breakdown of your body, is due to "overuse", , neither are likely.
The most common cause of altered behaviour of muscle, such as tightness, poor patterns of recruitment, and altered sensations, are the sequelae of spinalfacet joint hypomobility , referred neural events , brought about by a protective response of the vertebral spine. It is the nature of mammalian spines to have the means to increase the tone of paraspinal musculature , to limit movement of joints.( and by so doing limit the mechanical risks associated with percieved threat ) .
Your problem is most likely to be a referred pain/dysfunction event derived from inflammatory irritants operating at the L1 and L2 nerve roots. These irritants are the common product then , not of an injury as such , but of normal , powerful and quite non pathological protective spinal events. To reverse these events one needs to reacquire normal movements at L1 and L2. The best means is a manual therapy known as Continuous Mobilisation. This is most often accomplished over one to three treatmets by a suitably qualified therapist , ideally a physiotherapist. , By this means spinal facet joint movements are restored and these protective responses turned off. Inflammatory pain issues are quickly resolved ( pain and abnormal behaviour can usually be seen to resolve in as little as ten minutes )Much time and wasted money and effort is often directed at the groin in cases like yours, where poor understanding may prevail, and the real and likely prospect of referred pain not fully explored.