I started back exercising for the new year but after the first day my thighs were a little sore now i hurts about a 6/10 to sit or stand and when i am walking i feel the muscle twitching they are also tender to touch and feel really weak?

Too much exertion: Most likely exertion after few months of rest or too enthusiastic exertion will cause muscle pain which leave after few days with supportive treatment like plenty of fluids ,analgesicslike tylenol,ibuprofen etc. But if urine output is less and the urine is high colours like reddish/brownish , need to r/o rhabdomyolysis which is breakdown of the skeletal muscles. In that case need to go to your PCP