Is my upper back pain due to heart problems or posture problems?

Muscles!!!! Think flesh/tissue and not bone/ligament/disc with chronic pain! began selfcare with a wellness program of vits, magnesium glycinate, sleep hygiene, exercise, self massage, chiropractor, yoga, heat, epsom tub soaking, stretching all are needed. In my practice I use acupuncture and myofascial tissue release with trigger points w lidocaine.