Is there any theory about how a cell created and exists after the Big Bang or after Solar System forming or even after Earth forming?

Yes, there are a few theories on how the first cell formed on Earth. The one I believe is most popular is also in my opinion the easiest to explain. To simplify it a great deal, chemicals in Earth's oceans mixed together near the many volcanic vents present deep below. These chemicals would form amino acids naturally through being mixed around, and these amino acids are the building blocks of life. Proteins could also be formed by this method, and eventually these could combine into an incredibly basic cell. It is a very interesting topic, and I encourage you to look further into both the formation of cells and evolution to get a better understanding. This explanation is far from in-depth, but can be a good starting point.

Yes there is a theory or better yet PROVEN FACT. How life began in the Oceans from just a few

proteins, enzymes, and amino acids. Close to a Heat source like a Volcanic vent.

Known as the Primordial Soup Theory, it states that life began in a warm pond or ocean from a combination of chemicals and some form of energy. This led to the creation of amino acids, the building blocks of proteins. Proteins are essential parts of organisms and participate in virtually every process within cells. This is supposed to have happened at least 3.8 billion to 3.55 billion years ago.

The early earth had conditions that resulted in chemical reactions occurring frequently in the oceans. Scientists call the ocean at that time the primordial soup because experiments show that many of the organic chemicals could have been created naturally Under certain conditions, protenoid microspheres will spontaneous form. These proteinoid microspheres is currently viewed by some as possibly how protocells evolved. Protocells are not quite cells but they do have a membrane and therefore chemical reactions can occur within this enclosed space without being affected by chemicals outside of the microspheres. Whether this is how cells actually evolve we may never know the oldest known fossils are already identifiable as bacteria

Why do you mix-up your question with the Big Bang and solar system formation? That's kind of like asking for the whole history timeline of how the agricultural revolution (10,000 BC) leads up to the modern Honda car production plant in 1982 AD, with particular emphasis on the ascension of Julius Caesar and the Later Tang dynasty.

It's not that scientists can't give you the whole timeline, because they can. It's just that the areas of study are so wildly separated, and the connections between them are so complicated, that it would take months or even years to give even an overview.

Only God can provide the spark of life. You can mix amino acids and minerals together all you want and it still won't create life. We were made by an Intelligent Designer.