Bone & Muscle problems

I m 18 years old boy and i m very thin, and i want to gain weight. i started eating alot(i mean enough) and do basic exercise like pushups on regular basis at home using samrt phone application...but i m still same as before. Now i m lookin for a mass gainer to gain weight but dont its safe for me or not. if safe then what how much quantity should i required. Or if not safe i m not gonna bother that again.

I have pain nd stiffness behind the left knee since one month. In morning, when I wake up, there is no pain nd stiffness... But when I finished my morning routine work( 6am to11am) like cooking, dusting, brooming, floor cleaning with mop, washing clothes etc.,after that I can't bend my leg easily, I can't crawl on bed from left leg without support ... I can't get up or stand just after sitting. After getting few steps with support I feel normal...but now these days I can't too much walk...

I have cold since 2 days. I am now having a waist (back) pain. I am unable to bend, sit or stand straight. It's not paining continuously but there is a stretch n pulling effect

I was recently involved in the accident at work where I was paying between a dumpster and a garbage truck. I was diagnosed with leg abrasions. The swelling was immediate although no skin was broken. The swelling has since become irritated and has not subsided much. There is also another lump not protruding under the skin on the back of my thigh. It seems to be less irritated after I clean it but when I get home from work it's usually pretty itchy and irritated. Should I seek additional medical attention online research seems to be conflicting period thanks for your time.

The wooden plank fell directly on the centre of my leg With pain suddenly my leg started swelling up rapidly in that portion my whole leg is now swelled up I waited for 2 days i soaked my wound with hot water Third day it seemed fine no pain but suddenly when i went out of home it started swelling up again What to do? plz suggest

My shoulder got dislocated 4 weeks back.I undergone treatment and doctor suggested that u should undergo physiotherapy after 4 weeks .I shifted to other location.Do i need to consult doctor now?

I had a burn on my right ankle with the silencer of bike. The wound is 17 days old. In last 3 days therw aew blisters coming around the ankle and causing a lot of pain. Presently taking pain killer and Sefdin ( Antibiotic 300 mg) for last 6 days but no improvement

Can I get plaster after 10 days if there is any problem Please suggest me because after 10 days I will be at home at now I am in college campus.

I'm suffering from too much back pain after my 2nd scissor delivery so want really some good treatment

Once in my childhood i was fell down on some rocks and thus i got supracondylar fracture but it was not recovered or treatment was not well and thus it is not straighten yet after 8 years. So what should i do to recover it