Many speakers use 'myself' instead of I/me when they are unsure what to use:
Myself and John were there. I think many use this because they know 'John and me' is wrong, though commonly used, but aren't really sure what to say. The same would occur with the object: He spoke to John and myself.
In both cases, there is a more correct form, so while they are being used interchangeably, it is a usage that many criticise.
Student or Learner