Infinite regress and debunking karma

[Sicnoo0]

I'll be operating from a Buddhist POV for this post because I know next to nothing about Hinduism.

According to the theory of Karma, all suffering is caused by your own misdeeds (any acts causing suffering to others) in a past life or this life.

Okay, I have two fundamental issues here.

1) I assume by "suffering" you're referring to "duhkha"? I don't agree with the translation of duḥkha you're using. It's the most common one, but I think "unease" and "unsatisfactoriness" are more accurate translations. IMO, "suffering" is a bit too harsh of a word. Duhkha refers to the everyday unease that comes with being human, of our consciousness/higher awareness compared to other animals. It's "the void" that most people fill with alcohol, work, sex, kids, video games, junk food, etc. Suffering sounds much more intense to me, like mourning a loved one or getting stabbed.

2) Duhkha is not caused by your misdeeds or misdeeds in past lives. I mean, don't get me wrong, there is some relation because ultimately everything is interdependent. But one of the main tenants of Buddhism is that duhkha is inherent to life regardless of one's karma. Buddhism claims to offer a path that decreases this duhkha.

I was going to respond to the rest of your post but I realize that I don't have to, the rest is predicated on the first assumption, which I take fundamental issue with.

Both Hinduism and Buddhism claim that there is a theoretical catalog of your good deeds and misdeeds. In Hinduism, whatever has been catalogued of your history of good deeds and misdeeds determines what will happen in your life, as far as good things happening to you or bad things happening to you is concerned. 

However inappropriate the definition may be, I ask that we understand I'm using the word 'suffer' to encompass any and all instances of a sentient being experiencing a state that we would intuitively describe as a negative subjective experience. The slightest feeling of inconvenience qualifies. 

What can Buddhism say to the problem I pose by invoking the first ever sentient being to suffer? 
I presume that Hinduism claims that the first sentient being to ever suffer (call him Bob) only suffered as a consequence of his own past misdeeds. However, past misdeeds directly implies that there was a sentient being who suffered at the hands of Bob before Bob ever suffered. Therefore, any supposed first sentient being to ever suffer that I invoke cannot exist under Hinduism. I take it as a necessary logical fact that there had to have been a first ever sentient being to suffer. Since this is at odds with Hinduism, I reject the latter. 

My guess is that according to Buddhism, the first ever sentient being to suffer must have suffered for reasons unrelated to the deeds which that sentient being had committed up to that point. This completely avoids the problem that I've posed. 

Would it be fair of me to say that the Hindu conceptualization of karma is incompatible with the existence of a first ever sentient being to suffer?

Whereas the Buddhist conceptualization of karma seems perfectly compatible with there having been a first ever sentient being to suffer