Is it necessery to fallow one imam or one muslak? Are we rewarded just for reciting the Holy Qur'an?
We do not need to follow a particular school of thought. God Almighty has revealed the last religion of God on the Prophet Muhammad (sws) and has decreed it to be the final and purest form of guidance. He requires from human beings to study, ponder over and accept the truth revealed for them. God the Almighty says that God will not accept from us religions other than Islam. This demands that what forms part of the religion be made available for all till the day of Judgment for it is something they are going to be questioned about. We can explain this issue with the help of an example. If a teacher does not teach a specific matter to his students and then during the exam the students find questions they never heard they would be astonished. It would be gross injustice. This is why the Almighty has made the Prophet (sws) communicate the religion of God to entire generation of the Companions. It has since then been practiced and passed on through tawatur and consensus of all the succeeding generations till it reached us. Nowhere do the four imams or other scholars fall as a necessary source to be read and studied.
Therefore, it is not necessary to study, understand and follow understanding of any of these scholars. The religion, Islam, and my understanding of the same are different things. So is the case with the understanding of the four imams. The content of religion is but the Qur'an and the Sunnah. Though I am very much in debt to every scholar of the past who have done any sort of work in this field yet understanding the true and pure form of the religion doesn't hinge upon this endeavour.
Works of the scholars and experts in any field are always useful in understanding a given topic in the field. It would be extremely important for a student of physics to study and understand the views of for example Newton yet it cannot be held necessary qualification.
The religion of God has been made secure and available for all the people on earth. It cannot be said to be the property of any scholar or group of them. Islam and the understanding of Islam of different scholars are two different things. We must keep them separate and deal with them as such.
As for the question of being rewarded on reciting the words of the Qur'an, we believe that primarily the Book of God was revealed for guidance of mankind. The primary objective and basic use of the book is to study it with the purpose of seeking guidance. However, reciting it is also a form of worship. We know that we recite the Book in the Prayer. And we also know that all forms of worship are rewarded. On this basis we can say that we can be rewarded on merely uttering the words of God. However, this does not mean that we use it as mere formulas to be chanted to heap rewards without bothering to study it for guidance.