shoulder fatigue in crawl stroke?

Question
I am a newbie swimmer working to increase my laps.  It's mainly a winter sport for me, and I begin with kickboard laps, decreasing those and increasing crawl laps.  I swim 2 or 3 times a week, generally not consecutive days.

My problem seems to be that after a certain number of crawl laps (usually less than 10) I start to notice what I'm guessing is a rotator cuff inflamation the next day.  Is this due to improper technique and/or warmup?  I really want to continue with swimming and expanding lap capacity, but am afraid of causing long term joint troubles without knowing it.  

I have not taken private lessons, just tips from a swimming friend when we are at the pool together, and I've consulted a few books.  I failed most swimming lesson classes as a kid, so am excited to be progressing, and would like to continue doing so.  I am a 33 year old female in decent shape.

thank you in advance,

DeeAnn

Answer
DeeAnn--
This doesn't sound like a rotator cuff problem, it sounds more like a biceps tendonitis problem.  The main cause of this is you may be dropping your elbows when you are pulling through the water.  An easy, possible cure(if this is what is hurting), is to make sure you are leading with your hand and keeping it below your elbow when you pull through the water.  
Another suggestion is to warm up with a few laps of swimming before you start kicking.  This is because kicking with a kickboard puts stress on your shoulders and warming them up gets the joints more relaxed than just jumping in and kicking first.
You can also try kicking without a kickboard to eliminate the stress angles that a kickboard puts on your shoulders.
Hope this helps,
George