I love swimming and would rather swim than run. I just happen to be pants at swimming and reasonable at running.
I'm a member of a swim club and pay £15 a month for 2 swims a week which are coached. I get pointers on technique and help with pacing. So I'm happy.
As for injury - of course you can injure yourself swimming. Breaststroke is notorious for it - neck, back, hip, knee, shoulder. Plenty of swimmers who have given up on breaststroke due to injury.
I was told never to warm up with breaststroke as you are more likely to get injured this way.
I swim in a pool without tinny music, without kids and it costs £3.30 per swim outside of club time.
My favourite stroke is fly. If you want to injure yourself get your fly wrong.
When I run I don't notice what is going on around me. I don't notice the scenery or the noises. I'm totally switched off to everything apart from the running and the ground under my feet.