inner tremors a symptom?

In last 6 months i have some eery inner body tremors.Not too strong so i dont shake strongly,only after waking up and goes away when i stand up-- but very unsettling. Not hand nor feet , just inside my body; no spinning nor any chemical shortage like low in calcium nor high blood sugar. I am 80 y old, am relatively healthy however have high blood pressure, tinnitus, backaches, but play singles tennis and move and live healthy.. But those tremors are freaking me out bcz cld be early parkinsons symptoms.. Pls help me on this. best regards geza