Passout/dizy/lightheaded. Toy shake?

Suddenly feel like I am about to pass out, fallover, or faint. This happens b/w 4-5 days interval, with in a fraction of second I will recover. I will also feel as though my legs are weak & I might collapse & I feel like I am unsteady, feel like I am walking on unstable surface, or that it’s hard to keep my balance along with swollen kind of feeling in my feet. - This happens very often, in a week 3-4 days. Along with above 2 I have a squeezing kind of pain sensation in my right leg near ankle till knee. While I haven't passed out yet, still I think I might and this for sure frightens me. The same symptoms I can tell as a dizzy/lightheaded one’ that is like having a sudden feeling of being dizzy/lightheaded that then disappears. This symptom will come and go suddenly, come and longer, or come and remain for some time. This symptom will occur rarely, frequently, or persistently. Pressure around neck will be more & the head on top of my neck feels imbalanced, like a wooden toy shake