This question is an exact duplicate of:
When people chat in chat rooms, with the same name, our inboxes get full. It can also happen if 2 people with the same name reply to the same post (I think) but appreciate this is not common. My user name is Dave, and this is common here (as well as posts like How do I ping the right bob?)
This has been discussed many times on the SE sites.
For example, my inbox
The Dave in question (shown by question mark) is http://chat.stackexchange.com/users/171610/dave
Can we have an option within our profile to turn on / off chat room notifications (so that they don't appear in the notification box) but still appear by our icon beside the text box (within chat)