I'm super sensitive to cold. Air conditioning quickly gets extreme for me, pools and water can be torturous and in winter, I'm always bundled up. I have a hard time trying to explain why I don't like going swimming to others. They think I'm lazy or something, but it's honestly a struggle to build up the courage. I truly want to be able to get in the water and swim, but it's very painful. They don't understand, "yeah, it's cold to me too." So, I started to say it differently now.
"It's like brain freeze in my bones." Literally. It's painful and deep ache to be cold. It tends to get the point across, but people are very insistent of course. I love when swimming pools are heated so I can enjoy the water but otherwise it's completely unpleasant.
Never force yourself into a cold pool. Never let anyone force you. Don't listen to them; you shouldn't have to put up with pain for their enjoyment. If it were them in pain, they wouldn't want to go in either.