Should I send her this long heartfelt-message?

I'm 24, she's 23. We were together for 3 years. We broke up 3 months ago. She ended it due to unresolved arguments. I wanted to make it work but respected her opinion. We didn't speak after breaking up for the first 6 weeks as we needed space and time to think. When I felt ready (6 weeks after break up) I wanted to reach out to her and try work things out. She told me she was going travelling for 5 weeks (she's still travelling at the moment) so it was really bad timing and we chatted a little that night. She then stopped messaging me which really hurt. It was my bday yesterday and she wished me a happy bday - I tried to start a conversation with her after this which also failed. Between these periods its been no contact. She's now said "it's not fair to talk while she is travelling".

However I feel I need to send her a long message to get things off my chest. It'll be good for my mind and a big weight off my shoulders to fully express how I feel. I realise this would do more harm than good in terms of my efforts to get back with her but for my own mind I feel it is necessary.

Please could I send someone in a private message what I'd like to say to get their thoughts? Thanks.