Great job! I've edited in several parts :) 

The Dilemma of February! Why February sometimes has twenty-eight days and sometimes twenty-nine days [1]. 

The history of calendar assembly ing closely relates to resembles [2] Pakistan’s constitutional history. They are both It was also very tortuous & bumpy. Pakistan's democracy is still stumbling due to the military intervention & incompetent politicians :) but the calendar is in equilibrium now. Let's discover find the ambivalence behind [3] why the number of days varies in February.

1. In a title you should spell out numbers and “and”. I added sometimes before twenty-eight because it adds a symmetry that sounds nicer and makes more sense.. If February has sometimes 29 days.. then it follows that it also has sometimes 28 days.

2. closely relates to = this history of the calendar depended on or relates to Pakistan’s constitutional history. In this case what you mean is that they are both tortuous and bumpy… so they resemble each other = look or seem alike.

3. ambivalence doesn’t make any sense in this context because it’s not like February has an opinion on whether there should be 28 or 29 days. The word ambivalence implies that someone has conflicting opinions, feelings, beliefs about something. 

February was named after the Latin word "februum" which means purification via the purification ritual "zebra" which is held on the 15th of February during the on full moon. Let me share a myth associated with February. August is named after the emperor of the Roman Empire, Augustus Julius Caesar. At that time August had 30 days and February had 29 days. So Augustus realized decided that August should have 31 days instead of 30 so he stole 1 day from February and added it to August, at that time February was last in order. It was just a myth. [4] 

Forget platitudes [5] myths let's trace out what history says. In the ancient roman calendar there were only 10 months only comprising a year of 304 days. They used to consider winters as periods without months. monthlees period.[6] 

4. That February was the last in order doesn’t add anything and fits in awkwardly so drop that. Also, you already said it was a myth so no need to add that again.

5. What you said wasn’t a platitude it was a myth.

6. Monthless is not a word so you have to change the phrase around.

There is also a Gregorian Calendar, which was brought created by Pope Gregory XIII, in October 1582, that made making minor reforms in to the Julian calendar. This calendar leaves has 3 leap days every 400 years to bring the calendar more closer to lunar cycles (any one of the aspects or appearances presented by the moon as seen from Earth).[11] It changed the average length of a year from 365.25 days to 365.2425 days, a difference of 10 minutes and 48 seconds every year. The gregorian calendar is also called the western & and [12] christian calendar and is the most widely followed calendar followed in the world.

11. I think you can remove this as you don’t need to explain what lunar cycles are. If you do want to explain what lunar cycles are you should try to do so in a way that is more readable.. this seems like you just pulled a definition from a dictionary.