Hiya april,
Yes I agree with cookie. Palpitations and things like this can be brought on by any number of things. I doesn't mean they are actually related to any heart problem, nor does it have a connection most of the time with having a medical condition. Some medications can cause this to happen. If you have bought any OTC meds, then make sure they don't interact with any of your other pills.
ALso anxiety or stress can cause this to happen, and if you can learn to identify what it is that is bothering you, then this will help. Relaxation techniques too might be beneficial to you. I know when you are stressed or anxious, relaxing is this is nigh on impossible to do but you need to have coping strategies with this.
If it is very worrying then arrange for a heart scan. This might put your mind at rest.
Take care.
goldenwings