When is the proper time to ask for overtime pay?

Tweet

I work for a trading company since my graduation from college last July.As a freshman in the company,not knowing much,i didn't care much about the salary althouh it was not low,What i cared was what i would take the opportunity to study.So whoever asked me to do something ,i always dit it without any complaint,althouh sometimes i would turn he/she down politely.And i am a lucky guy,my manager is very nice to me,he always give me the opportunities to study.Because of my hard work,i'm up to my work now,and i got my salary rised this february. During the off-season,i have plenty of time to kill,but after that,i will have a lot of things to do,like now,everyday,i am on the run everyday,sometimes even have no time for a cup of water.I have been working overtime to nearly eleven'o clock every night,wiout overtime pay.Sometimes ,i really feel tired.For this ,i hope i can have my overtime pay.Do you think it is the proper time for me to ask for overtime pay?Anyone can give me a suggestion?