premium wordpress themes and plugins question

hello , i'm wondering is using a premium theme and plugins that i bought for a cheap price from someone (it comes with the license) will cause me any copyright problems in the future ?

I don't see a reason why it should if you have a license.

There is nothing to worry about as you have a license

If you purchased the theme you are purchasing the license to use it. If you purchase from someone else, then likely the license is void, and if you distribute the theme/plugins then that is another issue entirely. Although, unless you become a unicorn I highly doubt anyone would waste money or time on a $50 theme/plugin - the cost vs result just doesn't have adequate value.