Everytime I try to use my machine the thread bunches up underneath

SOURCE: problems with stitching

I think what you are describing is the bobbin thread is pulling up to the top of your work so the pretty side is getting ugly. If so, you may need to have the machine serviced and the tensions adjusted. You can adjust the bobbin tension, but if the problem is caused by a piece of lint or stray thread lodged in the proper place and it later comes loose, you just have to adjust it again.

SOURCE: bobbin thread bunches up creating a tangled mess under the plate

This could either be due to the bobbin being wound too loosely, or the tension on the top thread is too loose. This just happened to me the other day, and I thought it was the bobbin thread, but then I put another bobbin in with a different color than the top thread (this is a huge help in diagnosing thread issues), and I was surprised to find that it was actually the top thread that was a big loopy mess on the underside of the fabric. I fixed it by tightening the tension on the top thread (quite a bit), and everything was fine.

SOURCE: I have a viking Iris sewing and embroidery machine

When I had that happen, it turned out that I had not wound the bobbin thread correctly (it was not wound tight and smooth enough). Wound a new bobbin from scratch, and all worked fine.

SOURCE: husqvarna viking, interlude 435...unable to solve tension problem

Sounds like the tension unit is at fault. First check the bobbin tension by removing the bobbin case. Use a half-full to 3/4 full bobbin. Be sure it is threaded through the bobbin case with thread hanging straight down with tension spring on top. Tie the stitch plate to the end of the thread. If the thread pulls the bobbin out, the bobbin tension is too loose. If it does not move when "jiggling" the bobbin, it is too tight (which is not likely based on your description). Small screw (through an open hole) on the side of the bobbin case adjusts the tension of the bobbin case. Left for loose and Right for tighter. Otherwise, contact local authorized Husqvarna Viking dealer for their assistance. You can find the closest dealer at the Husqvarna Viking website - http://www.husqvarnaviking.com/us Good luck.

SOURCE: bobbin thread gets bunched up and loud clicking sound

The problem is never the bobbin when you have this problem. It's the top thread. Take the thread off the top of the machine and rethread the top. Make sure the small tension dial is on 4 or 5 (the larger dial on the front left is for the pressure on the foot, not the thread tension.) After you thread the machine, put the pressure foot down but NOT on the thread. Then pull gently toward the back of the machine. When you do, the needle should bend slightly backwards before the thread comes through the machine. If it pulls with no resistance you could simply have "fluff" or remants of thread between your tension discs. If you do, put the dial on zero and using an old needle, clean between the discs and try threading the machine again with the "pull test" I described earlier.
No tension on the top of the machine, lets the bobbin tension win and it pulls all the thread to the bottom of the fabric.