How would I find a repeater in my area (Pakistan)? Are there any web resources? Can I use repeaters to listen only (using an SDR)?
In some countries (like the US), there are numerous publications, websites and apps which list repeaters, but I don't know of such a resource for Pakistan. A good place to ask is probably the Pakistan Amateur Radio Society (PARS). Their website is: http://pakhams.com/
And yes, you can simply listen to a repeater with an SDR or any other radio capable of receiving the repeater's output frequency. In fact, if you do not have an amateur radio license then you are only allowed to listen, not transmit.