No you can read the  quran any time you want not only in ramadan even in normal days it's up to you when you want to read except the time of (jawal) it means from 11:45 am to approximately 12:40 pm or 1:00 pm no one knows the perfect time but majority tells that time as I mentioned above you can't read the quran in the time of  jawal because the sun is right on the above of the earth and it is forbidden to read the quran in the time of jawal but the time duration is depend on in which country you live what is  your region so it is better for you to ask a imaam of your area I hope it will help