Thanks for your query.
Firstly, pain in the neck and upper back are most likely due to spasm ("catch") of neck and back muscles. This usually happens due to either sleeping in an odd posture; or, a sudden jerk. A 4-5 days' course of muscle relaxants, such as Tramadol
or, better still : combination of ibuprofen
+ clorzoxazone along with warm compresses, will relieve you of the pain completely.
Your ECGs and Lipid profile
are NORMAL. So, relax and don't worry about having a heart disease
PROVIDED there is NO history of same in your family (parents, siblings).
If you still wish to reassure yourself, you may undergo TMT which is inexpensive and fairly accurate in excluding/confirming presence of heart disease.
Hope I have answered your query.
Dr. Rakesh Karanwal