Yes, money causes suffering in many. It is power and authority. Those possessing lots of money decide the direction where the world moves in. Yet, is money itself the problem? If you stop and think about it, money is just a tool. It's not any different from, let's say, a knife. It has a particular purpose - it's a means of exchanging items and services.
How does a knife even compare? Well, it's a tool, too. It serves to cut an item into pieces, to make holes, to grind something. But, when abused, a knife is a tool to cause injuries and death. Does this make it evil? Does owning a knife make you a sinner? Well, hardly anyone would agree.
Likewise, money is a tool. It can be used correctly, or it can be abused to cause pain and destroy lives. It's not money per se that is the problem. It's the user - the owner of wealth that can create dismay. Greed is the issue - the wish to obtain more and more money. The desire to be rich at any cost. Richness itself is not a problem, either. But it becomes an issue when one gains via abuse, i.e., by directly or indirectly stealing from others.
It is not about money, it is about us. As you said, money is just a tool. Sometimes we don't use it in correct way.