If you have something like that, there is nothing wrong with your PC but you usually have an issue with the grounding of your house electricity installation.
If you look at the power plug of your PC, you should see that there is the grounding part. This should be connected to the grounding part of your house. If the grounding is not connected properly to earth and to the whole house electrical system, you will get those shocks.
If your house is really old, this problem is quite common.