Chest Pains: Left Breast near Sternum

Hi there,
I would like to know if anyone could help me with this question..
For a long time now i've experienced mild chest pains near my sternum.
I can't be 100% certain of its more a stabbing pain or pressure pain but it comes and goes.
It's a very centralised pain with a burning sensation.
It does hurt more if i inhale and i've also been having phlegm on my chest so iv been coughing abit
in the mornings.

Another thing is sometimes whilst sleeping my whole body will jolt and il awake with a fright. I don't know if the chest pain and this is linked but its worth a mention as its also a little worrying.

Looking forward to hearing some advice on this..