Thanks for choosing health care magic for posting your query.
From the description that you have stated, it appears that you are very much bothered about your low weight.
First of all, try to understand that 63kg for a height of 5.10" is not bad and in the era where people are struggling to loose weight your problem is actually a boon.
Secondly amount of weight one has depends on the genetics and depends on the body constitution of your parents. If they are also thin then in that case, its difficult to gain weight in spite of all the efforts.
Regarding the investigations, thyroid
profile is something you can get done. If the thyroid levels are high then you may not gain enough weight and it needs to be corrected.
Eat diet with heavy calories like eggs, non-veg food, butter, ghee and rest leave it to your body to respond.
Hope I am able to solve your concerns.