Hello Sierralv77 , greetings from healthcaremagic.com  I am Dr Sourav Chakraborty and i have gone through your case scenario in detail and i will be answering your queries. Your BMI falls in just above normal / overweight category , you are of 23 years of age , since how long are you having this symptoms ? Do you have fever ? the pain you experience may mimic cardiac ailments but before jumping to a single conclusion lets rule out other possibilities. You did mention you have a somewhat stiff neck while swallowing , do you have similar feeling while taking solid food ? Also so you suffer acid reflux or burning sensation starting from neck and going lower down the chest. Please get a chest X ray for you that might actually reveal any thing significant. I don t know your lifestyle but as per your age i am rulling out ischemic heart disease for you and will only consider cardiac rythm disorders and valvular heart disease , so if you suffer from frequent palpitation/ throbbing sensation in your heart please get a ECG and an Echocardiogram with doppler spectral analysis done for you or visit a primary physician of your choice as clinical examination is very important for you alomng with lab work up. Check your blood pressure as well. Lastly i would like to throw some light upon anxiety attack as it can mimic almost anything at a younger age like yours. Hope i have been able to help you with your doubts and please do forgive me for grammatical errors , if any. Take care.