I have pain one right side of my chest. closer to the sternum, above the right nipple. it's like there's something tugging at the area. the middle of the upper back feels strained as well. but i have no difficulties breathing?

Need to examine: It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. It would be prudent to see your doctor. What you described suggests muscular issue. Try getting regular exercise of sufficient intensity to raise your core body temperature, i.e. sweating, that will loosen the muscles. Wish you good health!

Chest discomfort: I assume there has been no recent injury or strain. Your symptoms are rather nonspecific.It doesn't appear to be a breast tissue issue or a lung symptom at this time. That leaves possible mild rib cage inflammation such as costochondritis if there is tenderness of the rib and sternal border. Try applying warm compresses or liniment and take ibuprofen. See your MD as needed.