They mean the same. You wouldn't need the capital "o" in, "on top of that". It's very well written, and sounds more like business English, for informal or conversational writing/conversing, you could simplify it a bit. I would say that some of the barriers to my learning and improving English were; a lack of native speakers to practice with; few sources of practice material and a general lack of all English media. Also on top of that, I have to work for ten hours a day, which is obviously very tiring. Something like that. Sometimes if you use, "clever words" like, "conducive" you automatically cut your audience down, because they're not clever enough to know what they mean, or they're too lazy to listen. I mean English people, not other students, I never call students stupid. The general public in England, yea, they're stupid hehehe

There's another way of writing your sentences, as it seems to me that you want to express yourself formally. Here's my suggestion: The absence of an environment conducive to English learning severely limited my progress in learning English.The biggest barriers were the lack of an English media and native English speakers to chat with. In addition, I had to work 10 hours during the day and after work I had limited time to practice my spoken/written English. However I have been able to overcome these obstacles by.................