I received this refusal letter to my PLAB2 UK visa application

I really need your help!

I received this refusal letter to my PLAB2 UK visa application. Considering the reasons pointed out in this application:
1: I believe the consular officer did not take a look at my cover letter at all, and refused my application right away , since I had explained everything including my income, job, everything.
2: I have been told that the fact that I am from Afghanistan, a politically and economically unstable country, has played important role in my visa refusal. How come they judge our visa application based on the country we reside? It is not justice.
3. I have been refused a short term student visa prior to this which was completely on different occasion other than plab. Could it have affected my current application?
4. Should I talk to any solicitor and visa consultant for my next visa application? Do any of you know any solicitor who can help me regarding this?
Thank you in advance?