I had taken Dawnmarie's suggestion about how my machine was threaded. (Hey Dawnmarie I learned something new about the threading of my machine "Thanks) Sad to say that it didn't help with thread breakage. I'm using a Schmetz quilting needles 90/14. I have changed thread, tension, bobbins and needles. I'm going to give it some more time. I don't want to give up yet.
Thanks All for your suggestions.