Express a little first until you stop squirting milk everywhere. The fast flow you are getting could be too fast for him at this age and he will be choking on it. If you are boobs are swollen, mine with dd1 felt like footballs that were overpumped, then you may need a different hold to position his head better to the nipple. Again expressing a little will soften them up
Oh I do sympathise, it's a nightmare when they don't latch on properly. The first thing is you need a good breastfeeding midwife to help you. Can you contact the hospital or GP and ask for a local breastfeeding clinic? If you get the right advice it can really help.
My DSs were all tough to latch on and as a result I got cracked and bleeding nipples and it was very painful at first. They did toughen up and it got loads better and in the end was fine but the first few weeks were awful each time. With my DS4 a male midwife advised me to use cream all the time and this really helped make them more supple and not hurt. I also learned to get his head at the right angle and hold it quite firmly in the right place to stop him wriggling into the wrong angle again. This also helped with the pain. If your boobs are swollen you can try expressing a bit before you start to take the pressure off and make it easier for the baby.
I'm sure someone considerably more knowledgeable than will come soon, but I used to hand-express a little before latching DS on to soften the breast and lessen the force of the milk coming out. But soon enough DS managed to just gulp everything down.