Although i am no concussion expert, i am a nurse and would ask if with this increase in HR, did you have palpitations? Where you in pain? Were you well hydrated? Temperature? HR is affected by a lot of different factors and you can see HR increases with pain, dehydration, increase in temperature and even anxiety. If you had an irregular beat or palpitations, i would say that might warrant a conversation with your doctor. I also normally rest around 56-62 and notice that my resting HR during headaches will increase to 80's or 90s. I wouldnt be too worried about it. Im sure before your concussion you were a lot more active which would bring your HR lower while resting and assuming now you are not working out or doing strenuous activities as frequently since your concussion so your resting HR may increase slightly. Hope this helps