Suggest Treatment For Small Knot On Right Side If Shoulder Blade

I have a small knot on my right shoulder blade. I am not able to get rid of it and it is now affecting the right side of my back. I went for a massage and she was not able to get rid of it. The knot has been ongoing for many years but I am not able to get rid of it. I am 50 yrs old, 5 6 and 135 lbs. I work out 6 days a week doing treadmill and jazzercise. Thank you, Holly Benz