Can you keep from being Overweight if you can't Exercise due to medical conditions?

I’m having chest pain due to jogging. So i can’t do exercise especially these days i should not even try. Yesterday i tried alittle slow walking and even that hurt.

I’m going to the doc today.

But anyway, medical texts/tv/books/health magazines and the doctor himself say you should do at least 30 to 45 minutes of moderate exercise in order to keep in shape.

I’m in shape now because up to a 2 days ago i was exercising fine. But now i’m not gonna be able to do it.

So is there a way to not get overweight.. or is there no way out?

male in my early 30s