Well I work in the field too and I would strongly disagree that companies prefer to have drugs with side-effects so that they can make more money.

The reason there are so many side effects is that the drug acts at many more places other than where you need it to act for its benefit. They aren't really "side effects" but are what we would call extensions of the pharmacology of the drug or exaggerated pharmacology. So you need a drug to act at point B in order to benefit you. Unfortunately, point B exists at more parts of the body than just the one you are looking for. Or point C and D are physiologically very similar to point B and so the drug has effects there too.

The body is a very complex thing and finding a drug that does one thing only at one point only in the body, is damn near impossible. But trust me when I say that companies are definitely trying to find more exact mechanisms.