I'm a smoker for 15 years i'm 30 years old i have upper back pain on my shoulder blades and neck pain can it be lung cancer ?

Lung cancer: Yes. A chest xray is a good intitial test to look for signs of cancer, and may reveal the cause of your pain as well.

Sounds muscular, but: I would still see your PCP to discuss cancer screening possibilities, have a full physical, and discuss smoking cessation options. The sooner you quit, the lower your chances of cancer, and the more likely your lungs will return to pre-smoking health! Good luck