Could Lobha(craving) and Dosa(aversion) be working in tandem? Is wishing for a pain to go away an instance of aversion(Dosa) or an instance of craving(Lobha)? Or both working in tandem? 

ex: leg pain while doing sitting meditation.

Aversion is obvious, if the pain becomes unpleasant. But there is also the wanting for it to disappear(Vibhava Tanha) or the desire for the non painful state.

An Abhidhamma answer would be much appreciated.
If you want an abhidhamma answer, you have to speak in abhidhamma terms. &quot;Wishing for pain to go away&quot; is a sutta statement. It involves a wisher, and describes a sutta action.
lobha and dosa cannot arise in the same citta, certainly. They are mutually exclusive cetasika that arise in the javana cittas of the process of a single experience, and all of the javanas in any given thought process are said to be the same, since they arise from the same votthapana citta.

Only one type of citta runs for all seven occasions of the javana process.
-- Bhikkhu Bodhi, Comprehensive Manual of Abhidhamma, p. 157

One act - of wishing for pain to go away, for example - may contain many such processes, each one with javana of different makeup.  So, in wishing for pain to go away, there are probably multiple consecutive lobha, dosa, and moha cittas - though all unwholesome cittas contain moha.