Its probably just coincidence. There are many things that can cause a temporary mild pain or ache in one or both balls: sometimes its as simple as poor sleeping position. Yes, its also possible you might have just hit a raw nerve while forcing yourself: stop jerking off for a day or two and see if the pain passes. If it stays the same or gets worse, or your scrotum feels swollen/tender, you may need medical attention.
Masturbation habits do not usually change suddenly: you're born multiorgasmic, or you're not. Prior to this thread, did you typically
just fine from a single orgasm, or have you always needed a second or third to feel a good release? If you've ALWAYS needed a second or third, no problem, but if this is a new thing with you, it could create trouble for you like ball pain and sore glans.
A good orgasm starts in your brain: sexuality is highly affected by mood, stress, medications, sleep patterns, etc. All my life, I've had days or weeks where my desire to
is intense but masturbation leads to a mediocre orgasm thats unsatisfying. When that happens, I don't worry about it: I realize I'm just having an "off" moment or period and it will pass quickly.
Forcing myself to
again in a short time occasionally helps, but then I'm too sensitized to do it again for several days. I'd rather shrug my shoulders at a poor jackoff session than mess up my chances to enjoy it again the next day. Try to just roll with your own patterns: if you have a dull orgasm, forget about it and try again tomorrow instead of trying to force a good one right away. As long as you have a hand, a cock, and a scrotum you'll have a chance at "better next time": don't overthink this. It isn't an issue unless we make it one.