Is the sound a muffler problem if it is coming from the middle of the car?

I found a 98 Honda Accord for sale by owner for $1000. It has a sound coming from the middle, and I think that I could feel some vibration coming from the shift stick. Owner said that it is the muffler.

What do you think?

I think you should take it to a certified mechanic for a pre-sale inspection. Likely cost you a $100 but could potentially save you thousands in repairs. The owner would FIX the muffler and sell it for more if it were so simple.

A partially plugged catalytic converter which by the way is in the middle of your car will cause the car to overheat and shake and vibrate. You can find out if it's the catalytic converter by starting the car and driving it a couple of blocks at night time and then coming back to your driveway and open the hood and see if you see anything glowing cherry red and look under the car and see if you see anything glowing cherry red. If so you know your catalytic converter is plugged up and you better do something about it really quick before you destroy your engine.

I think you need to get a qualified mechanic to do a pre-purchase inspection.

I know what you mean, I felt it too.

It's impossible to say what might be wrong without hearing the noise. It would be only a wild guess.

I would be able to tell if I could look under the car. That's what I think. The exhaust system and the shifter are not connected, but the transmission is and it will relay engine vibration. $1000 is pretty cheap for a car, except when it has expensive problems.

That would be a leak in the exhaust. The cat is in the middle and the muffler is at the end. Stick vibration is motor mounts gone. For 1000 bucks get ready for one thing after another. Not for you if you are asking basic questions of naivety.

Maybe you have no muffler after the CC. At the end of the day, you need a whole exhaust system. (That's what you get for living ina rust belt.)
I have bought all the parts and easily assembled the entire system, including CC and head pipe, online but if you need to buy even one part at normal retail it will kill your economy. Plus for the clamps.
Tell the guy the same car looks nicer to you for only $500.
But then if he says yes, prepare to slobber at his feet!

The "exhaust system" contains pipes and a muffler and probably a catalytic converter and maybe a resonator.

Any of these metal parts can make noise when defective.