I think you'll find the answer behind the wall! We had a problem with rotten wood behind our tub enclosure and found that the surround was installed improperly and water from the shower was leaking behind it causing the wood to rot. There could also be a problem with the Plumbing behind your wall - there could be a leaky pipe causing the problem.
Something you ate was rotten
cause it would get rotten
Cause its burnt.
It is much safer to take a bath than a shower cause in the shower you can slip so I would bath
Presence of sulphur.
Seats in the main valve body are leaking by, allowing water to go to the shower head.
No. Sounds like the catalytic converter is going bad. Rotten egg smell is a sign
full block of main drain. shower is lowest open area for back up to occur.
Technically it could be on the other side of the shower wall, but common sense would tell you this is not a good idea.
you have trash in your line take the shower head off and remove trash or possibly in water valve at shower
It would have to be the controls or the shower head. Distance from the heater or size of supply lines shouldn't have much affect. The only variable would be the control or shower head and either one could have a flow restrictor in it or both.
changing a shower valve can be sometimes impossible with out cutting a hole in the wall behind it. If you have a shower valve that is leaking through the valve and out of the shower head when shut off then I recommend trying to find new cartridges or replacement seals for the valve. If you need to replace the shower valve then I would cut a hole in the sheet rock behind the shower valve big enough so you have enough room to replace it. Sometimes if you can't get behind the shower wall and your water pipe isn't galvanized then it might be possible to change the valve through inside the shower but it can be a real struggle and most of the time you will need a wider trim plate. If you don't have much experience in soldering or using pex pipe and fittings then I would save you a headache and call a service plumber.