Terbinafine needs to be taken for 12 weeks (3months) for toe nail infections. Also fungal infections do take a lot of time to heal. Maintain good hygiene and adhere to the prescription for better results. As you have not provided much details on intermittent chest pain, I will explain in a general way. Terbinafine can cause dyspepsia in about 5% of patients that can cause intermittent chest pain. If the chest pain is related to any cardiovascular disease, that type of pain might not be attributed to terbinafine or the incidence is very rare. Hope the above information clarifies your doubts. Thanks.