can doctors change lab results?

If you're that worried, then just go to a different doctor and get a second opinion.

Not sure, if they can tamper with results, but my mums doctor told us (without proof) all this medical crap, so we would pay heaps for treatment or whatever, and we went elsewhere one time, and that doctor told us, she didn't even have half those problems her original doctor told her she had...then again, he was a very commercial doctor..

You can get the records from the lab, independently of the doctor.

"Tampered" with results is illegal.
Not likely to happen.

"Misinterpreting" can happen...it's not illegal. That's where a good relationship with your provider comes in.
Order your records and check on things for yourself.

I dont think they can. The medical technologist prints it all out for the doctor and either gives it to you or forwards it to the doctor. But idk, people do crazy things, why dont you confront your doctor or talk directly to the laboratory technician?

As a doctor, it's not really plausible that a doctor would be able to do that. I suppose he could exaggerate the clinical significance of an abnormal result but he really wouldn't be able to alter results as your lab specimens would be processed by a lab