Can be orthostatic effects.
Giddiness can be due to low BP, Pathology of inner Ear, Vertibro basilar insufficiency, Spondilytis
Muscle twitch is mostly benign and due to low Potassium and Magnesium along with dehydration.
Next Steps
Rule out Orthostatic Hypotension
Ear abnormalities
Hydrate properly. Coconut water can help
If still symptoms persist consult a cardiologist for Holter