Why not? You won't be able to trademark "doors" if you sell doors. But if you make it, day the name of your band, you can. It doesn't stop people from using the word doors in relation to well doors, or a door company. But it does stop someone else for using it for another band name. Basically you can't trademark a common word in a common usage, but you can trademark it for an uncommon usage. Now whether you should or not is a different story. Common words don't help SEO much.