I have the same thing athough mine is located more like 8" below the collar bone and I have had it for years. It is not that the pain is constant, in fact, most of the time I am not even aware of it, but when I touch that area it is definitely there. I concluded hat it is really too close to the surface to be heart related.
Hello and hope you are doing well.
If with movement you are getting pain it is likely to be an inflammation of the skin, subcutaneous tissue or the bone. This can happen with injury, repetitive activity or an infection of the skin. Sometimes it can be costo-chondritis, inflammation of the sterna rib junction. If the pain is aggravated with work or exercise then it could be due to cardiac pain. But when in doubt always best to have it checked. So please consult your primary care physician who may ask for an EKG or a treadmill test to rule out a cardiac cause for the pain.
Hope this helped and do keep us posted.