Surfing injuries - Rotator Cuff/Surfers ear

I have been seeing stuff about potential rotator cuff injuries from surfing/swimming on this forum quite a bit. I have looked it up on the internet but cant decipher the medical jargon so can someone please explain to me what I need to do to avoid this - and possibly what it is as it seems fairly common. I dont excersise regularly but when I do I tend to go for it so am quite injury prone.
Also, I have managed to find stuff on 'surfers ear' which I looked up after a very choppy day at Boscombe where I was very aware that water was just flushing straight into my ears when I turned my face away from the waves - it actually hurt. The info I have seen looks pretty scary to be honest, I had an outer-ear infection last year, not related to surfing but didnt finish the course of antibiotics (tut tut I know!) and expected it to clear itself up - kind of has (ish).
Does anyone wear the earplug things I have seen on the net, has anyone had problems with this?
P.s im not a hypochondriac (not much! haha) just want to be well informed.
Also, I have managed to find stuff on 'surfers ear' which I looked up after a very choppy day at Boscombe where I was very aware that water was just flushing straight into my ears when I turned my face away from the waves - it actually hurt. The info I have seen looks pretty scary to be honest, I had an outer-ear infection last year, not related to surfing but didnt finish the course of antibiotics (tut tut I know!) and expected it to clear itself up - kind of has (ish).
Does anyone wear the earplug things I have seen on the net, has anyone had problems with this?
P.s im not a hypochondriac (not much! haha) just want to be well informed.