Thanks for your health concerns.
It is quite abnormal for a young, helthy, athletic female like yourself to have an elevated resting heart rate like that; it is difficult for me to make a definite connection between a concussion
and a persistent abnormal heart rate
several weeks after the acute event, but I definitely recommend you to seek medical attention for further testing. Basic tests that likely would be ordered include a 12 lead resting EKG to see what you baseline heart rhythm is and perhaps a Holter monitor
(portable EKG) to see how your heart behaves over a 24-48 hour period.
Hope this is useful, wish you the best health,
Dr Brenes-Salazar MD