One of the most important things in stroke technique when it comes to freestyle and avoiding shoulder injuries is to bend your elbows underwater during the pull. This is proper form and will keep you from putting your shoulder in an awkward position that leads to a rotator cuff problem. Swimming only freestyle at all of your workouts may seem like a good idea if you are training for a triathlon, but I would not recommend it.
Because frequent free style swimming may cause injury to your shoulder.

Most sports come with injuries to accompany them. Although swimming is, by most standards, not a sport associated with high risk of injury, it does have its own problems. For swimmers, by far the biggest source of sidelining swimming injuries is the shoulder.
I was a competitive swimmer for 14 years, sometimes doing double workouts and 15,000 meters per day. I swam mostly freestyle and backstroke. I never had a shoulder problem until my college years. I had been training with pull buoy and paddles throughout my freshman year of college. I started getting a little pain in my left shoulder, but being 19 and feeling invincible, I swam through the pain and was sure that a little rest after the season would fix me right up. Well I did take the rest and ended up in a lot more pain when I resumed swimming a few months later! The doctors said it was rotator cuff tendonitis. I rehabbed and within a few more months I was back to swimming every day, but my shoulder has never been the same since.

Girish,

I had much the same experience with my shoulder as you. I saw numerous physical therapists over the years, and it wasn't until I was about 22-23 that a grad student at a local university sorted out my problem with me-- my posture was terrible. Years of being a freestyle swimmer had pulled my shoulders forward. Fixing my posture was a huge improvement, but to this day I still have some soreness in there when I do a little more laps than usual.

It is very dangerous Injury.
Most of player left swimming due to this Injury.
Fantastic post thanks for sharing i like this article.

Oops, I swim freestyle like all the time. So, keeping my elbows bent during the put will help prevent it? That sounds like something I don't want to get.

Medical Alarms
Shoulder injury is quite common among swimmers mainly due to fact that swimming strains the shoulder muscles. The best way of preventing these types of injuries is by strengthening your shoulders by doing the proper stretching exercises before swimming.

One of the most important thing to remember before swimming, is that you do the complete the warm up and cool down swim before you do any other type of workout. Another way of avoiding shoulder injuries is by using the proper swimming techniques. A common mistake done by most swimmers (and which causes shoulder problems) is not bending the elbow when doing the underwater pulls. This puts a lot of stress on the shoulders and it is important that you leave out the swimming stroke that leads to the shoulder injury.

Swimming is not a high impact sport but the shoulder is under a lot of stress mainly with senior people who should take care that they implement the proper techniques when swimming.

I've had this issue and now my shoulder is clicking once in awhile when doing arm circles.