Ever heard of "blue balls?"
That's a slang term for vasocongestion, which can happen to both men and women when they become aroused (it's a normal part of arousal), and it's what you're describing here.
You can alleviate those symtpoms pretty quickly by masturbating to orgasm, taking an analgesic like ibuprofen or tylenol, or just 20 minutes or so of rest.
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