Can you heat orange juice?!

Yes you can but it will taste different.
It is often used in cooking.

I remember when I was little and had a very bad sore throat, the doctor suggested drinking hot orange juice as a folk remedy.

It wasn't pleasant, nor did it help. Fortunately my mom also tried it, exclaimed "My god, that's awful!" and gave me a bowl of ice cream instead.

I wouldn't heat O.J. to drink it, yuck! But if you let it simmer it will reduce down into a syrup that you can make a citrus vinaigrette with or a citrus syrup for pancakes, waffles or french toast! Yummy!

Yeah, it'll taste bad. Unless YOU personally would like it. Everyone's different.
It is nasty though.

I squeeze orange juice over my salmon to saute it sometimes. So you could heat the oj, but if you're just going to drink it, I don't think it would be good. Better cold.

Well I'm sure you can, but I can't imagine it tasting any good . I mean it would be like a warm orange - not right

i wouldn't :/ but if you like it drink it