Can somebody help interpret this dream for me please?

Water is symbolic of calmness, purity, serenity. So not necessarily does this dream really have to do with your sister and your boyfriend doing anything but subconciously, something might be interrupting serenity in your life, your ability have peace.

Is there something internally bothering you that doesn't necessarily involve your sister or boyfriend? Because it could be a sign for you to just be careful about your surroundings. Dreaming about people close to you could be a sign there you have fear something may stir up in the future, not necessarily happening right now.

Because you mentioned it was your older sister, are you two in any way competitive or do you ever get angry at her certain sibling circumstances as her being older so she gets to do this or talked to a certain way because this could be a factor and your boyfriend is someone you truly care about so it could just be symbolic that you feel tense and stress right now. These two people in the water where water is again, symbolic of peace, creates an interruption of peace by people around you. This doesn't necessarily have to be true but you might have trust issues. I could be completely wrong but in the dream you're helping other people out which means you're at work and doing good will while there is something posing a threat behind your back.

Something going on in your life may be bothering you and the rest of this you may be able to define yourself.

[The dream was at a pool in a community center and i was busy working with people and helping them]

Pool may represent your unconscious. Community center may be your family.

[when i move to the pool area and see my sister and my boyfriend naked in the pool, i quickly ask whats going on and i find out that my sister seduced my boyfriend and had sex with him.]

I see an oedipal theme here (two women competing for the love of one man - in childhood, the daughter feels competition with her mother for her father's affection). That this is your sister leads me to wonder if there is something family-oriented in the dream. I believe the pool area is where you're moving into deeper, earlier memories.

[when i found out in my dream my physical body felt the most painful pain in my chest that i have ever felt in my life.]

This sounds like extreme anxiety/panic due to fear of some loss that would be catastrophic. I am thinking it could be a very early fear from a time when you were helpless.

[feels betrayed by sister]

I don't know if you meant during the dream, or after you woke up. IMO it's another example of the oedipal theme in the dream.

I think it means you are alittle insecure about where you stand with your boyfriend. It might mean you are litteraly afraid he likes your sister. You may be harboring feelings of resentment towards your sister. If he has cheated in the past, it may be a reflection of your fears for furture infedelities.

the first part of the dream is that u didnt do nothing wrong. the second part is that she already did it with him. and the third part is she didnt like u even asking what happend so felt the pain. good luck. or maybe that she is going to and noting u can do about it.... good luck..........Hotti

maybe your sister is really betraying you..

who knows..

dreams sometimes tell the truth.

I might feel subconsciously that might happen.....also, God speaks to us sometimes in DREAMS. it's in the BIBLE!!

maybe youre worried she will do that?