I tried to sew through too many layers of material (like 4 avg thickness) and it stopped feeding so I heard the bobbin jam. Now when I run the machine, I hear a grinding noise in the bobbin case/shuttle hook area. What did I do?

"jamming" Is typical when bobbin thread has escaped the case tension spring. Are you sure its the bobbin thread? Loop and nesting on bottom side is usually top thread tension too loose or uneven feed from top thread spool which if severe enough can also jam the hook. If unsure which thread is at fault, try using a different color top thread.

Comment here and I'll assist further if need be.

Depending on your machine, your bobbin spool might be too thick
try plastic bobbins, they are thinner than matal ones

I don't think you'll get it to feed on a domestic sewing machine, the foam is going to be too thick and difficult to feed through. I've used an industrial Singer 20U to sew vinyl to 1/4" foam which has a dacron layer glued to it, ie like carpet underlay thickness. This was to make replacement seat covers for ride on mowers; the Singer was strong enough to sew through both layers in a straight stitch, I could manage to overedge it on my domestic Elna but need a roller foot to stop the vinyl from sticking to the foot, and a leather needle. Even then, it wasn't easy.

I would replace the needle anyway. It's hard to tell if one is bent or not.

Remove your feed dog/needle plate and the bobbin cover. Take out your bobbin and bobbin carrier.

Get out a magnifying glass and really examine. Look for thread ends in between moving parts.

Also check the thread pathways. Especially where the take up lever is hidden. I've heard of some ladies finding threads snarled up in that area which caused problems like this.

Good luck. If all else fails take it in for repair.

a part of the computer is malfuctioning, & needs to be checked
try a new needle
rethread the machine using every thread guide
clean under the needle plate & in the bobbin area for loose threads & lint

I own a signer simple and it is a great little machine but if not adjusted just so it will act up like this.

The three things that caused this were:

#1 tension on upper thread and bobbin casing were uneven.
#2 Thread was catching on bobbin casing (solution, generously oil the face of the casing where the latch to remove the bobbin is located.
#3 The material was too thick (denim, leather) or I was sewing through too many layers of fabric.

As a general rule of thumb with this machine I never sew through more than 4 or 5 layers. This is a great machine for quick fixes and mending, but if using for apparel and complex items it can be a bit finicky. I default to a sturdier machine in these instances.

--Some times you may have to use a neelde with a larger eye so that the thread will flow though the needle easier,
-Sometimes the clearance on the bobbin case stop has to be adjusted to allow for thicker thread,
-Be abundantly sure the top thread is through the discs on the top tension and not behind the tension devise, then increase the tension to a tighter position. if there are numbers on the tension, og to 5-8 so tyhat the thread will pull up into the fabric and not form loops under the fabric
-What type of thread are you using, possibly try a thinner thread
-check the bobbin as it spins in the bobbin case and after you have put the thread under the tension spring on the bobbin case, be sure the thread will pull out of the bobbin case relatively easily if not loosen the screw on the bobbin case ( righty-tighty/ lefty-loosey)
if all this fails you had better take it to an industrial sewing machine technician

Remove the needle plate and clean the feed dogs there could be fluff gathering.
Check your needle is not damaged.

Try a denim needle.

well i have done the same thing , all u need to do is if you see the screws that hold the bobbin area you un screwq thoes and get you a pair of scisors and cut around the knoted mess and all you do is work with it until it is all out and you dont realy want to pull on it to much you know just work it around so it gets lose so that you can cut it out thin you put it back together and try it out.