Zts hard to get in reverse

[ZTS 2002]

PLZ HELP:

HI EVERYONE HERE IS MY PROBLEM HOPE SOMEONE CAN HELP.
I have a 2002 zts put a performance clutch in about 20k ago. Ever since it has been difficult to get into reverse and backup lights only worked occasionally. It has become almost impossible to get into reverse backup lights never work and sometimes hard to get into any gear without shaking the S___ out of the shifter. I suspect cabels not adjusted correctly but not sure any help would be great.

Thanks:
Eric