Hey Badge are you under alot of stress where you keep tensing your neck? I had a walnut size knot for a few months b/c of the stress.. I wasnt lifting weights at that time so b/w the cardio, stress, etc... I always was adjusting and correcting myself and posture.
Pay attention to your posture and hunching and let me know if you think it could be a slight cause or even aggravating it... can you do additional stretching throughout the day? Or get to a masseuse or chiro ?