Next which test dones plz say??

Left Chest and left upper back pain everyday I am Male, 27 Years I have been having left chest pain and feeling of having heart attack for last 11 months and it never gone. I have visited 4 cardiology doctors (1 in emergency and 3 as a visit) every doctor has said there is no issues with the heart. I have got 20 ecg in 11 months, 3 months back 1 echo , this year janavary first 1 tmt and all came negative. All the doctors said that it is no heart prblm but pain not gones pain some times suddenly comes sharp gone... in seconds some times one minute :i dones 2 month s back this test  sugar test normal, renal function test normal, high sensitive Trophonin normal, chest x ray normal, tmt normal, i have fear of heart attack i have no bad habits even tea, coffe also... but why comes this prblm next which test dones...next which doctor i cunsulted, ???