I doubt if anyone knows which DIY ingredients sellers will ship to Pakistan, unless they're from Pakistan, too. Best thing to do would be check the Shipping Policies of each place recommended below and see if they do or not.
Here's some of the most often recommended by many on here:
For Nicotine Base -
Nude Nicotine
Wizard Labs
RTS Vapes
My Freedom Smokes
Carolina Extract
Heartland Vapes
EcigExpress
FOR PG and VG -
Bulk Apothecary
Essential Depot
Wizard Labs
Amazon
EcigExpress
For Flavorings -
Wizard Labs - Carry many brands
Bull City Flavors - Carry many brands
One Stop DIY Shop - Carry many brands and their own
EcigExpress
RTS Vapes
Flavoring Manufacturers' Own Websites -
The Perfumer's Apprentice (Same as The Flavor Apprentice)
Capella's
Flavor West
Flavour Art
Inawera
Hangsen
I'm sure other people will come along and post additional ones, too. But those will give you a start to check on International shipping.
EDIT: As far as needing laboratory equipment...IMO, save your money. You don't NEED flasks, beakers, etc. to make great DIY eliquid. For mixing using the volume method - If you have something to measure out ingredients (several syringes in 1mL, 3mL, 5mL, and 10mL are most common, with several blunt needle tips in 14ga and 16ga) and something to mix the ingredients in (the bottle you'll keep your mix in, or a cup you can easily pour ingredients from into your eliquid bottles, etc.)...that's all you need to use. If you use the weight method you'd need - a scale, maybe a small weight set to keep it calibrated, some pipettes to transfer liquids, and something to make to make your eliquid in (again...the bottle you want it in, a cup, etc.).
Obvious other things easily bought many places - a pair or 2 of latex or nitrile gloves and maybe a case or carrier to keep your bottles/vials of flavorings in. You'll also need some glass bottles to rebottle your Nic base in, to store for longterm use in your freezer. It'll come in larger containers, and needs to be rebottled into smaller bottles (many use 60mL, 120mL, or 240mL sizes) to put in your freezer. That way, only 1 small bottle at a time needs to be kept out of the freezer for mixing for several months usually (depends on how much eliquid you make & at what mg).