Hi, Sharon.
I have used subliminal recordings, CDs, DVDs, and Youtube videos and found many to be helpful in
relieving anxiety, helping to go to sleep, so I would think they are helpful in boosting self-esteem.
They can be self-hypnotic which I find a good way to overcome emotional problems.
Boosting self-esteem is, I believe mainly up to you. Do some journaling to learn why you have low self-esteem,
then deal with the issues. Unless you are a serial killer or crooked politician, I doubt you should have a low opinion
of yourself.
Also, write a list of the positive things you have done for people or accomplished in your education or work life.
Your back and other pains may come from a low self-esteem, but I suggest you also journal to discover if
you have repressed emotions such as anger, perhaps going back to your childhood.
Think good of yourself.