Such a pain is not caused by heartburn, asthma or chronic obstructive pulmonary disease (COPD). This type of pain is more commonly associated with nerve compression and/or inflammation, possibly in association with arthritis or disc degeneration of the spine. You should have x-rays of the chest and spine. You may want to seek consultation with a lung specialist or a neurologist.
Alo no weight loss or gain. Just pain fatigue and depression.