I've been having on and off pain under my breastbone, in my ribs and my shoulder blades that gets a bit better when i burp. could this be acid reflux?

Under sternum pain: Yes it is possible. You could see if over the counter omeprazole relieves the symptoms. Avoid caffeine, alcohol spicy foods smoking, fatty foods. In any event would get checked out by doctor urgent care this week to make sure it is not other causes like gallbladder, constipation( rare if normal BM), food intolerances ( may cause reflux), eosinophilic gastritis, rare and unlikely cardiac.