It's a mixed bag. There are three kind of karma. Our stored karma, the portion of that stored karma which we bring into this life, and the karma we create here that impacts our future lives. And "future lives" includes life in the astral--"the afterlife."
The problem I have with this concept of Karma is that it is very similar to the christian concept of heaven and hell. I'm sure most religions have a similar concept as their 'main plank'
Basically what they are saying is 'you've got a really bad deal in this lifetime but don't worry if you knuckle down and don't create any fuss about the unfairness of it all then after you're dead you will reap the rewards in the afterlife or maybe get reincarnated with extra bonus points'.
Maybe it is just a control mechanism whereby the few can control the many. It's a brilliant concept and has been very successful for thousands of years, but it does tend to empower those at the upper reaches of the pyramid at the expense of those at the lower. Therein lies my problem.