WHAT IS THE PROBLEM?

Compressor not clicking on and off ? If not sounds like your orfice tube filter could be partially clogged this filter is in the high side line of A.C system that is the small line. To remove there is a disconnect that takes a special tool to separate the line then you will need a pair of needle nose pliers to remove filter from inside line.

I replaced that. Still getting very high low side pressure with normal high side pressure.

Try cleaning your A.C condenser coil with a garden hose and nozzle or better yet a pressure washer your coil may be partially clogged with dirt and bugs causing little to no air flow across the condenser coil.

Check your Fan Clutch too. How hot is it where you are? If the Orifice Tube were blocked, you would have a very high High-side and a very low Low-side. I'd look for an air flow problem across the condenser - or just a 107 degree day will do it too.