Male Baldness Info

I’m an 18 yar old male and for the last couple months have been experiencing something weird. I’m not sure if this is natural hair loss or not.
I will have a painful irrititation in random spots on my scalp and when I have that pain if I run my hand through that location or pull the hair around that location a few strands of hair usually easily come out.
I’m not noticing large bald spots or anything, and baldness runs on my father’s side, but is it supposed to happen like this and come out after scalp pain? I also have a small bump that popped on up on the back of my head and I’m not sure if it’s related. Also some very sensitive scalp on the back of my head. I can’t even really lay down on the back of my head to sleep.

Hi, I’m 20 years old and ever since I was about 16 my hair started gradually getting more dry and sparse. It started out slowly but as I got older it became more noticable(to myself). At 19, I started losing more hairs and at 20 my hair and scalp is very dry and brittle. My hair has become more sparse, although it is not noticable, but by comparison it feels like 50% of my hair has decreased. When I run my fingers through my hair I can feel a dramatic difference. I used to have a more fuller head of hair and now I feel like it’s very spacy. I don’t know if I’m balding, and I am lead to believe its not male pattern baldness since my hairloss has been all over eqaully (not the typical male pattern baldness).
Another observation is my hair reacts to certain activities. If I work out (wieghts) I knotice my hair becomes more dry like I just fried it. If I’m in a situation where I’m stressed my hair also becomes fried. Lastly, any sexual activity the same happens.
My hair feels rough, and is stiff. This is making me go crazy. I want normal hair!!!
I’ve gone and seen a family practioner, and got a blood test and they told me everything was fine?! BUT its not !!?
Who can I see to really get some help?
Can anyone please help !?