Symptoms like you are describing should be evaluated. There are many places that can help you without insurance. Is there a University close to you with a Medical Branch? You should at least discuss this with your family doctor. Explain to the doctor that you are in the process of quitting smoking so that is taken into consideration when being evaluated. Take care, Ally
A heart issue can't be ruled out based on your symptoms. There could be a nerve spasm or pinching. In the process of quitting smoking can have an effect. During the quitting process people should consider the following physical symptoms of withdrawal as they were recuperating from a disease and treat them accordingly as they would any physical symptoms that include tingling in the hands and feet, heart palpitations, etc....
However, you may want to discuss the matter with your doctor to rule out any serious heart disease. Take care.