At 31, can my pain in the upper back pain be serious?

Hello doctor,

I am a 31 year old male. For about two weeks or more, I have been experiencing a mild nonspecific pain in my upper body. It is mostly at the upper back, at the center, and slightly towards the right. At times, it occurs in the middle and lower back, at the sides, behind the right upper arm, and occasionally around the chest and right collarbone. Mostly it is in the upper back at the center and slightly towards the right. The pain is mild and not at all severe or crippling. The feeling is sometimes of little stiffness, and sometimes a throbbing or pounding. I do not feel any trouble in doing my usual chores.

I have a habit of examining my body, pressing here and there to feel anything unusual, and on one such occasion, I found a couple of places on my chest that were painful when pressed deeply, but I do not feel anything unusual under the skin. In fact, several months ago, I had found a couple of other places on the sides that were painful when pressed deeply. I have a desk job, though I get up and move around quite regularly. I do not remember having any injury. I have never had any major accident.

I do not have any breathing difficulty and do not feel any pain or anything unusual while deep breathing. In fact, I have a habit of walking, and only a couple of days ago, I had walked 4 km at a stretch without any extra effort or discomfort. My queries are,

1. What may be the possible causes?
2. Could they be serious?
3. Is there any chance this has any connection with the lungs?

Hello doctor,

Thank you for the prompt response. I had indeed tested Vitamin D deficient last year. It was 12.5. As prescribed by my GP, I had taken Uprise D3 60K once a week for three months. I remember having a non-specific back pain that time too, for which I had consulted my GP, and he had suggested the vitamin D test. But, since I took the medicines as stated above, is it possible that I am still vitamin D deficient?

Kindly help.