Is back pain related to costochondrtitis ?

Maybe: The inflammation of costochondritis is in the joints between the ribs and the sternum. If this is a chronic problem it can lead to mid back problems as well (ribs attach back there too). Alternatively, the same inflammatory problem affecting the ribs may be affecting other joints as well, including the spine. See your chiropractor for therapy for both.

Generally no: When people are referring to costochondritis, they are generally talking about the cartilage in front attacked to the ribs and sternum. Usually it presents as chest pain. I am unaware of it presented as isolated back. It is possible mechanical changes indirectly effect the back. Also an inflammatory process like a rheumatologic process could effect both independently.