When your wearing a bracelet and it's starting to tingle or burn, it means that is reacting to something. Yes, it could be a warning but most of the time it means that the bracelet is reacting, it's doing what it should do.
This often happens to bracelets with crystals/rocks but it isn'tobligatory.
My mother has a bracelet for health and protection and whenever someone sick comes at her and the disease it's easy to take it, her bracelet burns her. But sometime it actually started to hurt her, it was too hot and that was because someone very sick came at her.
If it is only for luck, it could mean that it's bringing you luck or warning you of something bad, of something with energy opposed to what it brings(luck to bad luck).
If I said something wrong, I'm sorry.