Hello Ponycar,
Sudafed can cause tachycardia, zocor does not. Hopefully your nuclear stress test was an exercise stress test. Cardiac chest pain typically worsens with exertion and improves with rest. If the majority of your chest symptoms occur with rest and not exertion, this is typically not cardiac chest pain. If your chest pain occurs with rest and worsen with exertion, this is concerning for a cardiac source and merits further work up.
If you already have a negative nuclear stress test, the next definitive step is a cardiac cath. Sometimes caths are done to help relieve anxieties about coronary artery disease. It is important to remember that invasive tests have risks and should only be done if absolutely necessary.
I hope this helps.