Does kyphosis cause heart issues? Or c5-c6 herniated disc symptoms are similar to heart issues symptoms.

May be. Kyphosis does not cause any heart diease. How ever depending on the severity of kyphosis, people are more prone to get degenerative changes and arthritic changes in spine. This in turn can pinch the nerves and may cause referred pain in chest wall which would mascaraed as heart pain.
No ; maybe. Cervical kyphosis does not lead to heart issues but a symptomatic cervical disc herniation can present with similar symptoms to angina or myocardial infarction or heart attack such as neck and or arm pain with tingling which can lead to anxiety and altered breathing. If is not a time to take a chance but to go to er immediately to rule out a heart issue.