Ever since phone number tracking has become easy and accessible, people are worried that organizations such as the NSA might be tracking everyone's movements. It is quite true that they might be able to track anyone, but it is also true that not everyone is being tracked. The kind of tracking NSA would use to track someone may require use of sophisticated equipment. The equipment should be good enough to let NSA track a person secretly.
Like all other organizations, they will not track anyone who isn't a suspect or a VIP. They may receive a request to track someone from any other government organization, but that too if the reason is solid. The chances of the NSA tracking you right now are pretty small indeed. They would only be tracking you if you are an MP or some other government official or a high value target such as a drug dealer.
Remember that if you are being tracked by the NSA, you will not know about it. So you can first start by erasing anything that seems like Spyware and make sure that your calls are through a safe line. For mobile phones, getting a safe line is difficult. It is best that you simply do not speak about your secrets on phone and try to avoid using it when you are in danger of being tracked. How can you know whether the chances of you being tracked are high right now? That only you can answer. If you hang around VIPs or are a VIP yourself, then you should always make sure that all communication devices that you use are clean and free from Spywares.
Get your mobile phone checked from an expert or just refresh the operating system from time to time. Your mobile manufacturer should be able to tell you if you are being tracked or not, so they are the experts whom you should consult. The NSA can trap mobile signals and trace calls. You cannot protect yourself from this tracking method, but you can at least prevent majority of tracking attempts by using secure lines.