On 4/10 I started taking 25mg of hydrochlorothiazide in addition to my losartan. I seem to be tired all day now and my blood pressure drops to 86/66 within 30 minutes of taking the medicine and progressively increases through the day. This afternoon I started having mild chest pains on both sides. Is this something I should be worried about?

I too take hctz. It is a medication for fluid retention, I haven't had any problems. You might want to contact a doctor.