Is it normal to hear sloshing sounds after breast augmentation?

If there is no significant swelling or discomfort, this is probably just trapped air. This will resolve itself with your recovery.  It is not something to worry about and can be quite common.

What you are describing is quite commonly described after breast surgery.  The sensation of air trapped in the tissues is also commonly described. However, any significant increase in swelling/size would be of concern. Best wishes.

Usually the sucking or sloshing sound is due to a little bit of fluid left in the implant pocket from irrigation with saline or antibiotic fluid.  Very little fluid is needed to cause this sound.  The fluid absorbs over a week or so and the sound goes away.  No need for alarm.  Just mention this to your doctor so he/she is aware of your concern.