There are many movies and tv shows I've heard them saying but can't remember or figure out the way how to express that
I've experienced the same thing, so I can understand how it is
I believe there should be some sort of better phrase how to say that.
I've come up with
I can clearly understand that, because I've been through
I know how you feel, because I had experienced the same
Please, share your ideas
You could say:
I can empathise.
Empathy is different from mere sympathy in that it includes not just feeling sad or sorry for someone, but being able to recognize, understand, and share the thoughts and feelings of the other person. This is usually based on comparable experience, although not always.
You could add to that by saying...
I can empathise, I experienced the same / something similar.
... although you might not need to, as that is tacit in saying you can empathise. This may be a matter of opinion, but saying "I know, because I went through the same" immediately after someone sharing a problem with you could be seen as making yourself the subject of the conversation. Saying you can empathise is also a nice way of showing that they remain your focus.
A few less formal ways: "I have been there", "I have been in your position", or "I have been in your shoes".
From a bankruptcy lawyer's website: I understand the frustration and worry you are going through because I have been in your shoes. My mother was a school teacher and my father worked at a tire factory. They could not work any harder, yet our family often struggled to make ends meet.
(This is likely related to the saying "Before you judge a man, walk a mile in his shoes" or the purportedly Native American version "Never judge another man until you have walked a mile in his moccasins.")
More flippantly, there is "Been there, done that, [got the T-shirt]".
