I have purchaed a Flat with my saving but not disclose in Income tax. Is there any diffuculty willbe in future

Your question has no details as when you have purchased and for what price etc.,

If you have recently purchased the flat between 1.4.2006 till now, and if the cost of the flat is less than 30 lakhs (Govt. registration value), then there is no question of disclosing it. For the period after 1.4.2006, the new tax return forms ITR came into force and the ITR forms ask you to disclose any property purchased or sold for 30 lakhs and above only in the Shedule "AIR". If the property is less than 30 lakhs, then it is as good as you have declared the property.

If you are earning any rent on it, please show that rent and pay tax. You can also claim income tax deductions without any hesitation. You must keep all the record of the property purchased by you and you must be prepared to show the sources for your funds, bank loans etc.,

If passable, please go to some C.A and plan it neatly. Be happy. You have not done any thing wrong.

you will have nothing but problems only.

you have bought a flat out of your money earned by you and paid income-tax... if applicable...
i think you will not have any problem... if you have made payments by cheques... and not by cash...

Yes and No.

No, because, if you have used the savings from the income, on which you paid Income tax, then there should not be any problem, just make sure, that its relfected in the balance sheet you submit.

Yes, If the savings, you made were, from a non taxed income source.

Colsult a CA for getting it sorted out.