How can stiff neck be managed?

Hello doctor,

I have noticed some worrying symptoms lately. I am a 24-year-old male with no other known condition. I have noticed that the back of my neck feels very stiff and rigid when I sit at my desk with my head bent forward to read or look at the monitor, to the point that I feel the need have to stand or lie down to alleviate the feeling of discomfort. I have noticed that the rigidity disappears when I stand, walk or lie down. I have been feeling stiff since I have started studying again some days ago. I have spent the last two months without doing much (no physical activity or studying/working) due to the lockdown.

I also have widespread twitching in my thighs, calves and feet (both legs), on my back, on my chest, on my shoulders, in my arms, in my hands and in my tongue. I have felt twitching almost everywhere for a couple of years now. I also noticed that I am unable to put the heel of my left foot down when I stand or walk. I have had this issue for years and I was told it was due to tight calf muscles, although it feels more accentuated now. I would greatly appreciate any input you can give.

Thank you doctor,

Regarding the twitching:

I do not feel weakness in my body and I do not have troubles with activities involving my legs and feet like walking, standing, getting up or climbing stairs. I do not think that I have lost muscle mass anywhere as far as I can tell. I do not have sensory issues. I drink, on average, two cups of coffee per day. I do not feel any cramps.

Regarding the foot problem: I can always feel my foot resting on my toes. I am unable to stand on my left heel unless I force it down (it does not come as easy as with my right foot). It feels blocked in that position. I usually walk and stand on my tip toes because of this problem. I can walk on my heels with my right foot but hardly with my left foot. I do not think so, I can raise my let foot easily but not as much as my right foot. I take antihistaminic medicines for my allergies.