I want to just toss it into some indian food I have. Does it need to be cooked first or is it ok if it just warms up a bit when I throw it in the sauce?
Paneer can be used as is. Sometimes it is fried to extend shelf life. Cooks will also sometimes fry paneer until it is slightly brown and then put the fried cubes of paneer in hot water for a few minutes. This makes paneer very soft.
If you do cook paneer, it will not melt, like most other cheese varieties, because it's an acid-set cheese.
Well, I am Indian, so let me tell you this: in traditional North-Indian cooking (and this is where paneer is widely used), paneer is almost always cooked. Yes, no problem with not cooking it, but uncooked paneer is not a good dish. It is more a dry and stingy (for lack of a better word) cheese. So you see paneer or cottage cheese is best served cooked and well seasoned. That is where the real magic of cheese lies!
P.S. Google "paneer pakoda". This is a unique dish which will show you the versatility of the item.
It could be eaten raw, but is generally heated or cooked.
Personally, I find that pouring piping hot sauce over room-temperature paneer cubes works wonders for delicate sauce-based dishes, while cooking them gives best results and texture in dryer style dishes.
I have only used fresh homemade paneer, so I am not sure if differences in taste or texture with the store-bought stuff would yield different recommendations.
It depends on which dish you are using it in. In some you can fry and put in the sauce, in some you can put after the sauce is ready, in some you might have to marinate it for a few hours before you use it and in some you are required to cook it in the sauce for last few minutes before the dish is ready. Generally in the last case you need to be careful not to cook it too long else paneer cubes might break or crumble.
There is no black and white reply to that question. All depends on the dish being cooked or the chef. Some chef might put paneer before serving in shahee paneer or butter paneer but some might like to cook it in the sauce for last five minutes before serving. Generally it is cooked for very short time. The chances that it will be eaten raw is a little less but not impossible. It is put raw in salads and it is grated on several dishes. At the same time chances that it will be cooked for long is also less but not impossible. Like in some dishes it is deep fried or roasted.