Yes that is normal for a stock cooler. They give you mediocre coolers that on just suffice with a little headroom to keep costs down. If you want to really OC, you will need a new HSF. For 30 bucks you could get the Hyper 212+, it has very high performance for a small price.
Also i would suggest trying to keep temps below 65C. And if at all possible below 60C at all times. RUnning at 70C for too long may damage your CPU, as most AMD chips are rated 70-75C before they will start to burn up.