1. I play and create, say, a piano track and as I'm playing the pitch changes randomly.
2. I play it back and sometimes it's ok and then another time it will change pitch randomly at different places.
3. When I play a rehearsal it's always perfect, but when I try to record some parts are good and sometimes it changes pitch.
How can I determine if it's something in the program or maybe the midi controller.
 
 
Sonar X2 Producer    M-Audio Axiom 61 midi controller

Are these pitch changes random or the same notes all the time?

You can sort out whether it is in the controller or Sonar by using MIDIOx. If the note number shown as being transmitted in MIDIOx is different than the note number in Sonar, then it is a problem communicating with Sonar. If the note number in MIDIox is not the key you are hitting with the controller, then the problem is with the controller sending the wrong data. It is pretty hard to imagine why this could be happening in Sonar, unless you are actually missing a MIDI message due to a low MIDI buffer setting, and picking up the next note, but that should be pretty obvious in that you would have not only the wrong pitch, but actually missing notes/events. If it is playing the right number of notes, in the right timing that would rule out that explanation.
 
http://www.midiox.com/

the pitch changes are random

scasarella1
the pitch changes are random

Then that indicates that there is erroneous data being introduced into the midi stream do as suggested by slartabartfast and download and run Midiox program you should be able to see the midi stream and see what is actually being sent.

Sounds like the pitchbend lever/wheel on your controller is broken. It's pretty common. If you're handy with a soldering iron you can replace/fix the broken wire.

Sanderxpander
Sounds like the pitchbend lever/wheel on your controller is broken. It's pretty common. If you're handy with a soldering iron you can replace/fix the broken wire.

Good point, and even easier to troubleshoot. If you are not using the pitch bend wheel on your controller, there should be no pitch bend controller events in the Sonar event list. While you are at it look for aftertouch and other spurious events.
 
Another possibility is that you have some kind of randomized parameter running in the softsynth you are playing through Sonar.