What Causes A Click In The Arm While Lifting Weights?

I was working out 4 days ago and I was doing incline dumbell flyes when I lifted the weight up I felt a slight click in my left arm I have felt stuff like this before so I didn't think anything of iti did my reps fine but as I went to lower the weight I could feel some pain by my left collar bone and have felt this pain ever since but only when I raise my hand in front of me. And since then when I raise my hand up like that it feels like for a moment my shoulder bone are clicking together but it doesn't hurt when they click only when lifting something.could you please tell me what this is.