Brief Answer:
Can be stable angina.

Detailed Answer:
Hi
Thanks for asking query,
Have noted all your details.
Left sided chest pain,associated with neck pain and headache can be presentation of Angina.
I would sugest you to go for some of the base line tests of cardiology like
Tread mill test-An exercise stress test usually involves walking on a treadmill or riding a stationary bike while your heart rhythm, blood pressure and breathing are monitored,Any ischemia will be ruled out.
2d echo-Mobility of cardiac walls and overall functioning can be observed.
Combined together both these tests have 85% sensitivity in ruling out cardiac problem.
If these tests are normal
Pain can be because of overuse of muscles, muscle strain, or injury to the muscles, ligaments, and discs that support your spine.Poor posture(using pillow and soft mattress while sleeping). Pressure on the spinal nerves from certain problems, such as a herniated disc.
I would suggest you to go for a X ray cervical and thoracic region AP and LATERAL view, to rule out the above mentioned possibilities.
In case all these tests are normal then you should get a neurology consultation for headache and migraine.

Thanks

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